diff --git a/core/ass_file.cpp b/core/ass_file.cpp
index e2103ab86..02757cd37 100644
--- a/core/ass_file.cpp
+++ b/core/ass_file.cpp
@@ -89,7 +89,6 @@ void AssFile::Load (const wxString _filename,const wxString charset) {
 
 		// Generic preparation
 		Clear();
-		IsASS = false;
 
 		// Get proper format reader
 		SubtitleFormat *reader = SubtitleFormat::GetReader(_filename);
@@ -167,7 +166,6 @@ void AssFile::Save(wxString _filename,bool setfilename,bool addToRecent,const wx
 	if (setfilename) {
 		Modified = false;
 		filename = _filename;
-		IsASS = true;
 	}
 }
 
@@ -181,6 +179,43 @@ void AssFile::Export(wxString _filename) {
 }
 
 
+//////////////////
+// Can save file?
+bool AssFile::CanSave() {
+	// ASS format?
+	if (filename.Lower().Right(4) == _T(".ass")) return true;
+
+	// Check if it's a known extension
+	SubtitleFormat *writer = SubtitleFormat::GetWriter(filename);
+	if (!writer) return false;
+
+	// Scan through the lines
+	AssStyle defstyle;
+	AssStyle *curstyle;
+	AssDialogue *curdiag;
+	for (entryIter cur=Line.begin();cur!=Line.end();cur++) {
+		// Check style, if anything non-default is found, return false
+		curstyle = AssEntry::GetAsStyle(*cur);
+		if (curstyle) {
+			if (curstyle->GetEntryData() != defstyle.GetEntryData()) return false;
+		}
+
+		// Check dialog
+		curdiag = AssEntry::GetAsDialogue(*cur);
+		if (curdiag) {
+			curdiag->ParseASSTags();
+			for (size_t i=0;i<curdiag->Blocks.size();i++) {
+				if (curdiag->Blocks[i]->type != BLOCK_PLAIN) return false;
+			}
+			curdiag->ClearBlocks();
+		}
+	}
+
+	// Success
+	return true;
+}
+
+
 ////////////////////////////////////
 // Returns script as a single string
 wxString AssFile::GetString() {
@@ -280,7 +315,6 @@ void AssFile::Clear () {
 	}
 	Line.clear();
 
-	IsASS = false;
 	loaded = false;
 	filename = _T("");
 	Modified = false;
@@ -315,7 +349,6 @@ void AssFile::LoadDefault (bool defline) {
 	}
 
 	loaded = true;
-	IsASS = true;
 }
 
 
@@ -326,7 +359,6 @@ AssFile::AssFile (AssFile &from) {
 
 	// Copy standard variables
 	filename = from.filename;
-	IsASS = from.IsASS;
 	loaded = from.loaded;
 	Modified = from.Modified;
 	bool IsSSA = false;
diff --git a/core/ass_file.h b/core/ass_file.h
index 9ff61917f..a6bf3eff5 100644
--- a/core/ass_file.h
+++ b/core/ass_file.h
@@ -72,7 +72,6 @@ public:
 
 	wxString filename;
 	bool loaded;
-	bool IsASS;
 
 	AssFile();
 	AssFile(AssFile &from);
@@ -92,6 +91,7 @@ public:
 	void Save(wxString file,bool setfilename=false,bool addToRecent=true,const wxString encoding=_T(""));	// Save to a file. Pass true to second argument if this isn't a copy
 	void Export(wxString file);							// Saves exported copy, with effects applied
 	void AddToRecent(wxString file);					// Adds file name to list of recently opened files
+	bool CanSave();										// Return true if the file can be saved in its current format
 
 	int GetScriptInfoAsInt(const wxString key);
 	wxString GetScriptInfo(const wxString key);						// Returns the value in a [Script Info] key.
diff --git a/core/changelog.txt b/core/changelog.txt
index 421dc31c0..3618207d6 100644
--- a/core/changelog.txt
+++ b/core/changelog.txt
@@ -85,6 +85,7 @@ Please visit http://aegisub.net to download latest version
 - Text edit boxes in the subtitle editing area will now revert to unmodified if you restore the original text. (AMZ)
 - Re-arranged the controls in the subtitle editing area. (AMZ)
 - Right-clicking on the header of the subtitles grid will now bring up a popup menu that allows you to disable columns. (AMZ)
+- Saving back to SRT directly (that is, via "save", not "export" or "save as") is now allowed, as long as no data will be lost. (AMZ)
 
 
 = 1.09 beta - 2006.01.16 ===========================
diff --git a/core/frame_main.cpp b/core/frame_main.cpp
index 945bf5f71..2e2e085bc 100644
--- a/core/frame_main.cpp
+++ b/core/frame_main.cpp
@@ -561,7 +561,7 @@ void FrameMain::LoadSubtitles (wxString filename,wxString charset) {
 bool FrameMain::SaveSubtitles(bool saveas,bool withCharset) {
 	// Try to get filename from file
 	wxString filename;
-	if (saveas == false && AssFile::top->IsASS) filename = AssFile::top->filename;
+	if (saveas == false && AssFile::top->CanSave()) filename = AssFile::top->filename;
 
 	// Failed, ask user
 	if (filename.IsEmpty()) {
diff --git a/core/frame_main_events.cpp b/core/frame_main_events.cpp
index ee738b4f9..82f9d8510 100644
--- a/core/frame_main_events.cpp
+++ b/core/frame_main_events.cpp
@@ -1133,7 +1133,7 @@ void FrameMain::OnOpenStylingAssistant (wxCommandEvent &event) {
 void FrameMain::OnAutoSave(wxTimerEvent &event) {
 	// Auto Save
 	try {
-		if (AssFile::top->loaded && AssFile::top->IsASS) {
+		if (AssFile::top->loaded && AssFile::top->CanSave()) {
 			// Set path
 			wxFileName origfile(AssFile::top->filename);
 			wxString path = Options.AsText(_T("Auto save path"));
diff --git a/core/subtitle_format.cpp b/core/subtitle_format.cpp
index 52e6e64b1..3826b46eb 100644
--- a/core/subtitle_format.cpp
+++ b/core/subtitle_format.cpp
@@ -109,13 +109,6 @@ void SubtitleFormat::LoadDefault() {
 }
 
 
-///////////////////
-// Set if it's ASS
-void SubtitleFormat::SetIsASS(bool isASS) {
-	assFile->IsASS = isASS;
-}
-
-
 ////////////
 // Add line
 int SubtitleFormat::AddLine(wxString data,wxString group,int lasttime,bool &IsSSA) {
diff --git a/core/subtitle_format.h b/core/subtitle_format.h
index de26b7803..75f49a046 100644
--- a/core/subtitle_format.h
+++ b/core/subtitle_format.h
@@ -69,7 +69,6 @@ protected:
 
 	void Clear();
 	void LoadDefault();
-	void SetIsASS(bool isASS);
 	AssFile *GetAssFile() { return assFile; }
 	int AddLine(wxString data,wxString group,int lasttime,bool &IsSSA);
 
diff --git a/core/subtitle_format_ass.cpp b/core/subtitle_format_ass.cpp
index 748c08787..fb1695aab 100644
--- a/core/subtitle_format_ass.cpp
+++ b/core/subtitle_format_ass.cpp
@@ -88,9 +88,6 @@ void ASSSubtitleFormat::ReadFile(wxString filename,wxString encoding) {
 			throw wxString(_T("Error processing line: ")) + wxbuffer;
 		}
 	}
-
-	// Set ASS
-	SetIsASS(!IsSSA);
 }
 
 
diff --git a/core/subtitle_format_txt.cpp b/core/subtitle_format_txt.cpp
index 3610ce2c2..34026948e 100644
--- a/core/subtitle_format_txt.cpp
+++ b/core/subtitle_format_txt.cpp
@@ -58,7 +58,6 @@ void TXTSubtitleFormat::ReadFile(wxString filename,wxString encoding) {	using na
 
 	// Default
 	LoadDefault();
-	SetIsASS(false);
 
 	// Data
 	wxString actor;