diff --git a/aegisub/src/dialog_detached_video.cpp b/aegisub/src/dialog_detached_video.cpp
index 0e20ba131..2195ee161 100644
--- a/aegisub/src/dialog_detached_video.cpp
+++ b/aegisub/src/dialog_detached_video.cpp
@@ -75,7 +75,7 @@ DialogDetachedVideo::DialogDetachedVideo(FrameMain *par)
 	wxPanel *panel = new wxPanel(this,-1,wxDefaultPosition,wxDefaultSize,wxTAB_TRAVERSAL | wxCLIP_CHILDREN);
 	
 	// Video area;
-	videoBox = new VideoBox(panel);
+	videoBox = new VideoBox(panel, true);
 	videoBox->videoDisplay->freeSize = true;
 	videoBox->videoSlider->grid = par->SubsBox;
 
diff --git a/aegisub/src/frame_main.cpp b/aegisub/src/frame_main.cpp
index ff4f6817a..7d1bf55e3 100644
--- a/aegisub/src/frame_main.cpp
+++ b/aegisub/src/frame_main.cpp
@@ -535,7 +535,7 @@ void FrameMain::InitContents() {
 	BottomSizer = new wxBoxSizer(wxHORIZONTAL);
 
 	// Video area;
-	videoBox = new VideoBox(Panel);
+	videoBox = new VideoBox(Panel, false);
 	TopSizer->Add(videoBox,0,wxEXPAND,0);
 	videoBox->videoDisplay->zoomBox = ZoomBox;
 
diff --git a/aegisub/src/video_box.cpp b/aegisub/src/video_box.cpp
index cb96cc0bb..b67606aa9 100644
--- a/aegisub/src/video_box.cpp
+++ b/aegisub/src/video_box.cpp
@@ -65,7 +65,7 @@
 
 ///////////////
 // Constructor
-VideoBox::VideoBox(wxWindow *parent) 
+VideoBox::VideoBox(wxWindow *parent, bool isDetached) 
 : wxPanel (parent,-1)
 {
 	// Parent
@@ -125,11 +125,13 @@ VideoBox::VideoBox(wxWindow *parent)
 	visualToolBar->Realize();
 
 	// Top sizer
+	// Detached and attached video needs different flags, see bugs #742 and #853
+	int highSizerFlags = isDetached ? wxEXPAND : 0;
 	wxSizer *topTopSizer = new wxBoxSizer(wxHORIZONTAL);
 	wxSizer *topSizer = new wxBoxSizer(wxVERTICAL);
 	visualSubToolBar->Show(false);
-	topTopSizer->Add(visualToolBar,0,0,0);
-	topTopSizer->Add(videoDisplay,1,0,0);
+	topTopSizer->Add(visualToolBar,0,highSizerFlags,0);
+	topTopSizer->Add(videoDisplay,1,highSizerFlags,0);
 	topSizer->Add(topTopSizer,1,wxEXPAND,0);
 	topSizer->Add(visualSubToolBar,0,wxEXPAND | wxBOTTOM,4);
 	topSizer->Add(new wxStaticLine(videoPage),0,wxEXPAND,0);
diff --git a/aegisub/src/video_box.h b/aegisub/src/video_box.h
index 0b82a83cc..db4648b2e 100644
--- a/aegisub/src/video_box.h
+++ b/aegisub/src/video_box.h
@@ -83,7 +83,7 @@ public:
 	VideoDisplay *videoDisplay;
 	VideoSlider *videoSlider;
 
-	VideoBox (wxWindow *parent);
+	VideoBox (wxWindow *parent, bool isDetached);
 
 	DECLARE_EVENT_TABLE()
 };