diff --git a/aegisub/src/ass_file.cpp b/aegisub/src/ass_file.cpp
index 5c2eee457..661b0423e 100644
--- a/aegisub/src/ass_file.cpp
+++ b/aegisub/src/ass_file.cpp
@@ -83,7 +83,7 @@ void AssFile::Load(const wxString &_filename, wxString charset, bool addToRecent
 		// Get proper format reader
 		const SubtitleFormat *reader = SubtitleFormat::GetReader(_filename);
 		if (!reader) {
-			wxMessageBox("Unknown file type","Error loading file",wxICON_ERROR | wxOK);
+			wxMessageBox("Unknown file type","Error loading file",wxOK | wxICON_ERROR | wxCENTER);
 			return;
 		}
 
@@ -114,12 +114,12 @@ void AssFile::Load(const wxString &_filename, wxString charset, bool addToRecent
 	}
 	// Real exception
 	catch (agi::Exception &e) {
-		wxMessageBox(lagi_wxString(e.GetChainedMessage()), "Error loading file", wxICON_ERROR|wxOK);
+		wxMessageBox(lagi_wxString(e.GetChainedMessage()), "Error loading file", wxOK | wxICON_ERROR | wxCENTER);
 		return;
 	}
 	// Other error
 	catch (...) {
-		wxMessageBox("Unknown error","Error loading file",wxICON_ERROR | wxOK);
+		wxMessageBox("Unknown error","Error loading file",wxOK | wxICON_ERROR | wxCENTER);
 		return;
 	}
 
diff --git a/aegisub/src/command/app.cpp b/aegisub/src/command/app.cpp
index 9c4940b47..d858ac9e2 100644
--- a/aegisub/src/command/app.cpp
+++ b/aegisub/src/command/app.cpp
@@ -192,7 +192,7 @@ struct app_language : public Command {
 			OPT_SET("App/Locale")->SetInt(newCode);
 
 			// Ask to restart program
-			int result = wxMessageBox("Aegisub needs to be restarted so that the new language can be applied. Restart now?", "Restart Aegisub?", wxICON_QUESTION | wxYES_NO);
+			int result = wxMessageBox("Aegisub needs to be restarted so that the new language can be applied. Restart now?", "Restart Aegisub?", wxYES_NO | wxICON_QUESTION |  wxCENTER);
 			if (result == wxYES) {
 				// Restart Aegisub
 				if (wxGetApp().frame->Close()) {
diff --git a/aegisub/src/command/audio.cpp b/aegisub/src/command/audio.cpp
index ac5f63ffc..509ea2d00 100644
--- a/aegisub/src/command/audio.cpp
+++ b/aegisub/src/command/audio.cpp
@@ -105,7 +105,7 @@ struct audio_open : public Command {
 		}
 		catch (agi::UserCancelException const&) { }
 		catch (agi::Exception const& e) {
-			wxMessageBox(lagi_wxString(e.GetChainedMessage()), "Error loading file", wxICON_ERROR | wxOK);
+			wxMessageBox(lagi_wxString(e.GetChainedMessage()), "Error loading file", wxOK | wxICON_ERROR | wxCENTER, c->parent);
 		}
 	}
 };
@@ -123,7 +123,7 @@ struct audio_open_blank : public Command {
 			c->audioController->OpenAudio("dummy-audio:silence?sr=44100&bd=16&ch=1&ln=396900000");
 		}
 		catch (agi::Exception const& e) {
-			wxMessageBox(lagi_wxString(e.GetChainedMessage()), "Error loading file", wxICON_ERROR | wxOK);
+			wxMessageBox(lagi_wxString(e.GetChainedMessage()), "Error loading file", wxOK | wxICON_ERROR | wxCENTER, c->parent);
 		}
 	}
 };
@@ -141,7 +141,7 @@ struct audio_open_noise : public Command {
 			c->audioController->OpenAudio("dummy-audio:noise?sr=44100&bd=16&ch=1&ln=396900000");
 		}
 		catch (agi::Exception const& e) {
-			wxMessageBox(lagi_wxString(e.GetChainedMessage()), "Error loading file", wxICON_ERROR | wxOK);
+			wxMessageBox(lagi_wxString(e.GetChainedMessage()), "Error loading file", wxOK | wxICON_ERROR | wxCENTER, c->parent);
 		}
 	}
 };
@@ -165,7 +165,7 @@ struct audio_open_video : public Command {
 		}
 		catch (agi::UserCancelException const&) { }
 		catch (agi::Exception const& e) {
-			wxMessageBox(lagi_wxString(e.GetChainedMessage()), "Error loading file", wxICON_ERROR | wxOK);
+			wxMessageBox(lagi_wxString(e.GetChainedMessage()), "Error loading file", wxOK | wxICON_ERROR | wxCENTER, c->parent);
 		}
 	}
 };
diff --git a/aegisub/src/command/recent.cpp b/aegisub/src/command/recent.cpp
index b8ec89106..ceb1390a6 100644
--- a/aegisub/src/command/recent.cpp
+++ b/aegisub/src/command/recent.cpp
@@ -75,7 +75,7 @@ struct recent_audio_entry : public Command {
 		}
 		catch (agi::UserCancelException const&) { }
 		catch (agi::Exception const& e) {
-			wxMessageBox(lagi_wxString(e.GetChainedMessage()), "Error loading file", wxICON_ERROR | wxOK);
+			wxMessageBox(lagi_wxString(e.GetChainedMessage()), "Error loading file", wxOK | wxICON_ERROR | wxCENTER, c->parent);
 		}
 	}
 };
diff --git a/aegisub/src/command/subtitle.cpp b/aegisub/src/command/subtitle.cpp
index 38053fdbf..bed2a8e1a 100644
--- a/aegisub/src/command/subtitle.cpp
+++ b/aegisub/src/command/subtitle.cpp
@@ -335,13 +335,13 @@ static void save_subtitles(agi::Context *c, wxString filename) {
 		c->ass->Save(filename, true, true);
 	}
 	catch (const agi::Exception& err) {
-		wxMessageBox(lagi_wxString(err.GetMessage()), "Error", wxOK | wxICON_ERROR, NULL);
+		wxMessageBox(lagi_wxString(err.GetMessage()), "Error", wxOK | wxICON_ERROR | wxCENTER, c->parent);
 	}
 	catch (const char *err) {
-		wxMessageBox(err, "Error", wxOK | wxICON_ERROR, NULL);
+		wxMessageBox(err, "Error", wxOK | wxICON_ERROR | wxCENTER, c->parent);
 	}
 	catch (...) {
-		wxMessageBox("Unknown error", "Error", wxOK | wxICON_ERROR, NULL);
+		wxMessageBox("Unknown error", "Error", wxOK | wxICON_ERROR | wxCENTER, c->parent);
 	}
 }
 
diff --git a/aegisub/src/command/video.cpp b/aegisub/src/command/video.cpp
index 99b867ab4..8ec459aaf 100644
--- a/aegisub/src/command/video.cpp
+++ b/aegisub/src/command/video.cpp
@@ -154,7 +154,7 @@ struct video_aspect_custom : public validator_video_loaded {
 		}
 
 		// Sanity check
-		if (numval < 0.5 || numval > 5.0) wxMessageBox(_("Invalid value! Aspect ratio must be between 0.5 and 5.0."),_("Invalid Aspect Ratio"),wxICON_ERROR|wxOK);
+		if (numval < 0.5 || numval > 5.0) wxMessageBox(_("Invalid value! Aspect ratio must be between 0.5 and 5.0."),_("Invalid Aspect Ratio"),wxOK | wxICON_ERROR | wxCENTER);
 
 		// Set value
 		else {
diff --git a/aegisub/src/dialog_export.cpp b/aegisub/src/dialog_export.cpp
index fd2ddabb4..dc72c5b8c 100644
--- a/aegisub/src/dialog_export.cpp
+++ b/aegisub/src/dialog_export.cpp
@@ -157,16 +157,16 @@ void DialogExport::OnProcess(wxCommandEvent &) {
 	catch (agi::UserCancelException const&) {
 	}
 	catch (const char *error) {
-		wxMessageBox(error, "Error exporting subtitles", wxOK | wxICON_ERROR, this);
+		wxMessageBox(error, "Error exporting subtitles", wxOK | wxICON_ERROR | wxCENTER, this);
 	}
 	catch (wxString const& error) {
-		wxMessageBox(error, "Error exporting subtitles", wxOK | wxICON_ERROR, this);
+		wxMessageBox(error, "Error exporting subtitles", wxOK | wxICON_ERROR | wxCENTER, this);
 	}
 	catch (agi::Exception const& err) {
-		wxMessageBox(err.GetMessage(), "Error exporting subtitles", wxOK | wxICON_ERROR, this);
+		wxMessageBox(err.GetMessage(), "Error exporting subtitles", wxOK | wxICON_ERROR | wxCENTER, this);
 	}
 	catch (...) {
-		wxMessageBox("Unknown error", "Error exporting subtitles", wxOK | wxICON_ERROR, this);
+		wxMessageBox("Unknown error", "Error exporting subtitles", wxOK | wxICON_ERROR | wxCENTER, this);
 	}
 
 	EndModal(0);
diff --git a/aegisub/src/dialog_fonts_collector.cpp b/aegisub/src/dialog_fonts_collector.cpp
index 7bea42a13..541f4bd0d 100644
--- a/aegisub/src/dialog_fonts_collector.cpp
+++ b/aegisub/src/dialog_fonts_collector.cpp
@@ -271,16 +271,16 @@ void DialogFontsCollector::OnStart(wxCommandEvent &) {
 			}
 
 			if (folder.FileExists())
-				wxMessageBox(_("Invalid destination."), _("Error"), wxICON_EXCLAMATION | wxOK);
+				wxMessageBox(_("Invalid destination."), _("Error"), wxOK | wxICON_ERROR | wxCENTER, this);
 			if (!folder.DirExists())
 				folder.Mkdir(0777, wxPATH_MKDIR_FULL);
 			if (!folder.DirExists()) {
-				wxMessageBox(_("Could not create destination folder."), _("Error"), wxICON_EXCLAMATION | wxOK);
+				wxMessageBox(_("Could not create destination folder."), _("Error"), wxOK | wxICON_ERROR | wxCENTER, this);
 				return;
 			}
 		}
 		else if (folder.IsDir() || folder.GetName().empty()) {
-			wxMessageBox(_("Invalid path for .zip file."), _("Error"), wxICON_EXCLAMATION | wxOK);
+			wxMessageBox(_("Invalid path for .zip file."), _("Error"), wxOK | wxICON_ERROR | wxCENTER, this);
 			return;
 		}
 	}
diff --git a/aegisub/src/dialog_selection.cpp b/aegisub/src/dialog_selection.cpp
index 934653557..5ecb64018 100644
--- a/aegisub/src/dialog_selection.cpp
+++ b/aegisub/src/dialog_selection.cpp
@@ -254,7 +254,7 @@ void DialogSelection::Process(wxCommandEvent&) {
 	}
 
 	if (count == 0)
-		wxMessageBox(message, _("Selection"), wxOK);
+		wxMessageBox(message, _("Selection"), wxOK | wxCENTER, this);
 	else
 		wxGetApp().frame->StatusTimeout(message);
 
diff --git a/aegisub/src/dialog_spellchecker.cpp b/aegisub/src/dialog_spellchecker.cpp
index b43784b62..b5e497bdd 100644
--- a/aegisub/src/dialog_spellchecker.cpp
+++ b/aegisub/src/dialog_spellchecker.cpp
@@ -92,14 +92,14 @@ DialogSpellChecker::DialogSpellChecker(agi::Context *context)
 	// List of supported spellchecker languages
 	{
 		if (!spellchecker.get()) {
-			wxMessageBox("No spellchecker available.", "Error", wxICON_ERROR | wxOK);
+			wxMessageBox("No spellchecker available.", "Error", wxOK | wxICON_ERROR | wxCENTER);
 			Destroy();
 			return;
 		}
 
 		dictionary_lang_codes = spellchecker->GetLanguageList();
 		if (dictionary_lang_codes.empty()) {
-			wxMessageBox("No spellchecker dictionaries available.", "Error", wxICON_ERROR | wxOK);
+			wxMessageBox("No spellchecker dictionaries available.", "Error", wxOK | wxICON_ERROR | wxCENTER);
 			Destroy();
 			return;
 		}
diff --git a/aegisub/src/dialog_style_editor.cpp b/aegisub/src/dialog_style_editor.cpp
index 4af9ef2e8..c40546d85 100644
--- a/aegisub/src/dialog_style_editor.cpp
+++ b/aegisub/src/dialog_style_editor.cpp
@@ -428,7 +428,7 @@ void DialogStyleEditor::Apply(bool apply, bool close) {
 		for (unsigned int i=0;i<styles.Count();i++) {
 			if (newStyleName.CmpNoCase(styles[i]) == 0) {
 				if ((store && store->GetStyle(styles[i]) != style) || (!store && c->ass->GetStyle(styles[i]) != style)) {
-					wxMessageBox("There is already a style with this name. Please choose another name.", "Style name conflict.", wxICON_ERROR|wxOK);
+					wxMessageBox("There is already a style with this name. Please choose another name.", "Style name conflict.", wxOK | wxICON_ERROR | wxCENTER);
 					return;
 				}
 			}
diff --git a/aegisub/src/dialog_style_manager.cpp b/aegisub/src/dialog_style_manager.cpp
index 1368eb32e..4521b55e9 100644
--- a/aegisub/src/dialog_style_manager.cpp
+++ b/aegisub/src/dialog_style_manager.cpp
@@ -374,7 +374,7 @@ void DialogStyleManager::OnCatalogNew() {
 
 	// Make sure that there is no storage with the same name (case insensitive search since Windows filenames are case insensitive)
 	if (CatalogList->FindString(name, false) != wxNOT_FOUND) {
-		wxMessageBox(_("A catalog with that name already exists."), _("Catalog name conflict"), wxICON_ERROR|wxOK);
+		wxMessageBox(_("A catalog with that name already exists."), _("Catalog name conflict"), wxOK | wxICON_ERROR | wxCENTER);
 		return;
 	}
 
@@ -746,7 +746,7 @@ static void do_move(Cont& styls, int type, int& first, int& last, bool storage)
 	else if (type == 4) {
 		// Get confirmation
 		if (storage) {
-			int res = wxMessageBox(_("Are you sure? This cannot be undone!"), _("Sort styles"), wxYES_NO);
+			int res = wxMessageBox(_("Are you sure? This cannot be undone!"), _("Sort styles"), wxYES_NO | wxCENTER);
 			if (res == wxNO) return;
 		}
 
diff --git a/aegisub/src/dialog_timing_processor.cpp b/aegisub/src/dialog_timing_processor.cpp
index 35e02a395..fa8108558 100644
--- a/aegisub/src/dialog_timing_processor.cpp
+++ b/aegisub/src/dialog_timing_processor.cpp
@@ -324,7 +324,7 @@ std::vector<AssDialogue*> DialogTimingProcessor::SortDialogues() {
 			wxMessageBox(
 				wxString::Format(_("One of the lines in the file (%i) has negative duration. Aborting."), i),
 				_("Invalid script"),
-				wxICON_ERROR|wxOK);
+				wxOK | wxICON_ERROR | wxCENTER);
 			sorted.clear();
 			break;
 		}
diff --git a/aegisub/src/frame_main.cpp b/aegisub/src/frame_main.cpp
index 2178467e4..e5788665c 100644
--- a/aegisub/src/frame_main.cpp
+++ b/aegisub/src/frame_main.cpp
@@ -214,7 +214,7 @@ FrameMain::FrameMain (wxArrayString args)
 	StartupLog("Possibly perform automatic updates check");
 	if (OPT_GET("App/First Start")->GetBool()) {
 		OPT_SET("App/First Start")->SetBool(false);
-		int result = wxMessageBox(_("Do you want Aegisub to check for updates whenever it starts? You can still do it manually via the Help menu."),_("Check for updates?"),wxYES_NO);
+		int result = wxMessageBox(_("Do you want Aegisub to check for updates whenever it starts? You can still do it manually via the Help menu."),_("Check for updates?"), wxYES_NO | wxCENTER);
 		OPT_SET("App/Auto/Check For Updates")->SetBool(result == wxYES);
 	}
 
@@ -326,20 +326,20 @@ void FrameMain::LoadSubtitles(wxString filename,wxString charset) {
 		context->ass->Load(filename,charset);
 	}
 	catch (agi::FileNotFoundError const&) {
-		wxMessageBox(filename + " not found.", "Error", wxOK | wxICON_ERROR, NULL);
+		wxMessageBox(filename + " not found.", "Error", wxOK | wxICON_ERROR | wxCENTER, this);
 		config::mru->Remove("Subtitle", STD_STR(filename));
 		return;
 	}
 	catch (const char *err) {
-		wxMessageBox(wxString(err), "Error", wxOK | wxICON_ERROR, NULL);
+		wxMessageBox(wxString(err), "Error", wxOK | wxICON_ERROR | wxCENTER, this);
 		return;
 	}
 	catch (wxString const& err) {
-		wxMessageBox(err, "Error", wxOK | wxICON_ERROR, NULL);
+		wxMessageBox(err, "Error", wxOK | wxICON_ERROR | wxCENTER, this);
 		return;
 	}
 	catch (...) {
-		wxMessageBox("Unknown error", "Error", wxOK | wxICON_ERROR, NULL);
+		wxMessageBox("Unknown error", "Error", wxOK | wxICON_ERROR | wxCENTER, this);
 		return;
 	}
 }
@@ -448,7 +448,7 @@ void FrameMain::OnVideoOpen() {
 			LOG_D("video/open/audio") << "File " << context->videoController->GetVideoName() << " has no audio data: " << e.GetChainedMessage();
 		}
 		catch (agi::AudioOpenError const& err) {
-			wxMessageBox(lagi_wxString(err.GetMessage()), "Error loading audio", wxICON_ERROR | wxOK);
+			wxMessageBox(lagi_wxString(err.GetMessage()), "Error loading audio", wxOK | wxICON_ERROR | wxCENTER);
 		}
 	}
 }
diff --git a/aegisub/src/main.cpp b/aegisub/src/main.cpp
index ae885bb8f..4414cf7b7 100644
--- a/aegisub/src/main.cpp
+++ b/aegisub/src/main.cpp
@@ -336,7 +336,7 @@ static void UnhandledExeception(bool stackWalk) {
 #endif
 
 		// Inform user of crash.
-		wxMessageBox(wxString::Format(exception_message, filename), _("Program error"), wxOK | wxICON_ERROR, NULL);
+		wxMessageBox(wxString::Format(exception_message, filename), _("Program error"), wxOK | wxICON_ERROR | wxCENTER, NULL);
 	}
 	else if (LastStartupState) {
 #if wxUSE_STACKWALKER == 1
@@ -345,7 +345,7 @@ static void UnhandledExeception(bool stackWalk) {
 			walker.WalkFromException();
 		}
 #endif
-		wxMessageBox(wxString::Format("Aegisub has crashed while starting up!\n\nThe last startup step attempted was: %s.", LastStartupState), _("Program error"), wxOK | wxICON_ERROR);
+		wxMessageBox(wxString::Format("Aegisub has crashed while starting up!\n\nThe last startup step attempted was: %s.", LastStartupState), _("Program error"), wxOK | wxICON_ERROR | wxCENTER);
 	}
 #endif
 }
@@ -362,7 +362,7 @@ void AegisubApp::OnFatalException() {
 }
 
 void AegisubApp::HandleEvent(wxEvtHandler *handler, wxEventFunction func, wxEvent& event) const {
-#define SHOW_EXCEPTION(str) wxMessageBox(str, "Exception in event handler", wxOK|wxICON_ERROR|wxSTAY_ON_TOP)
+#define SHOW_EXCEPTION(str) wxMessageBox(str, "Exception in event handler", wxOK | wxICON_ERROR | wxCENTER | wxSTAY_ON_TOP)
 	try {
 		wxApp::HandleEvent(handler, func, event);
 	}
diff --git a/aegisub/src/subs_preview.cpp b/aegisub/src/subs_preview.cpp
index 82eabb3b7..c03832f00 100644
--- a/aegisub/src/subs_preview.cpp
+++ b/aegisub/src/subs_preview.cpp
@@ -141,7 +141,7 @@ void SubtitlesPreview::OnSize(wxSizeEvent &evt) {
 		wxMessageBox(
 			"Could not get any subtitles provider for the preview box. Make "
 			"sure that you have a provider installed.",
-			"No subtitles provider", wxICON_ERROR | wxOK);
+			"No subtitles provider", wxOK | wxICON_ERROR | wxCENTER);
 	}
 
 	subFile->SetScriptInfo("PlayResX", wxString::Format("%d", w));
diff --git a/aegisub/src/video_context.cpp b/aegisub/src/video_context.cpp
index 7e4677c05..21889b507 100644
--- a/aegisub/src/video_context.cpp
+++ b/aegisub/src/video_context.cpp
@@ -162,7 +162,12 @@ void VideoContext::SetVideo(const wxString &filename) {
 		else if (sx % vx != 0 || sy % vy != 0) {
 			switch (OPT_GET("Video/Check Script Res")->GetInt()) {
 			case 1: // Ask to change on mismatch
-				if (wxMessageBox(wxString::Format(_("The resolution of the loaded video and the resolution specified for the subtitles don't match.\n\nVideo resolution:\t%d x %d\nScript resolution:\t%d x %d\n\nChange subtitles resolution to match video?"), vx, vy, sx, sy), _("Resolution mismatch"), wxYES_NO, context->parent) != wxYES)
+				if (wxYES != wxMessageBox(
+					wxString::Format(_("The resolution of the loaded video and the resolution specified for the subtitles don't match.\n\nVideo resolution:\t%d x %d\nScript resolution:\t%d x %d\n\nChange subtitles resolution to match video?"), vx, vy, sx, sy),
+					_("Resolution mismatch"),
+					wxYES_NO | wxCENTER,
+					context->parent))
+
 					break;
 				// Fallthrough to case 2
 			case 2: // Always change script res
@@ -216,10 +221,10 @@ void VideoContext::SetVideo(const wxString &filename) {
 	catch (agi::UserCancelException const&) { }
 	catch (agi::FileNotAccessibleError const& err) {
 		config::mru->Remove("Video", STD_STR(filename));
-		wxMessageBox(lagi_wxString(err.GetMessage()), "Error setting video", wxICON_ERROR | wxOK);
+		wxMessageBox(lagi_wxString(err.GetMessage()), "Error setting video", wxOK | wxICON_ERROR | wxCENTER);
 	}
 	catch (VideoProviderError const& err) {
-		wxMessageBox(lagi_wxString(err.GetMessage()), "Error setting video", wxICON_ERROR | wxOK);
+		wxMessageBox(lagi_wxString(err.GetMessage()), "Error setting video", wxOK | wxICON_ERROR | wxCENTER);
 	}
 }
 
@@ -417,7 +422,7 @@ void VideoContext::LoadKeyframes(wxString filename) {
 		config::mru->Add("Keyframes", STD_STR(filename));
 	}
 	catch (agi::keyframe::Error const& err) {
-		wxMessageBox(err.GetMessage(), "Error opening keyframes file", wxOK | wxICON_ERROR, NULL);
+		wxMessageBox(err.GetMessage(), "Error opening keyframes file", wxOK | wxICON_ERROR | wxCENTER, context->parent);
 		config::mru->Remove("Keyframes", STD_STR(filename));
 	}
 	catch (agi::FileSystemError const&) {