diff --git a/libs/wxutil/FileChooser.cpp b/libs/wxutil/FileChooser.cpp
index d9a7e20f16..8b0c6ee91b 100644
--- a/libs/wxutil/FileChooser.cpp
+++ b/libs/wxutil/FileChooser.cpp
@@ -66,81 +66,96 @@ void FileChooser::construct()
 	// Make default extension lowercase
 	string::to_lower(_defaultExt);
 
-	int defaultFormatIdx = 0;
-	int curFormatIdx = 0;
+	if (!_open && _fileType == filetype::TYPE_MAP_EXPORT)
+	{
+		assembleMapExportFileTypes();
+	}
+	else
+	{
+		assembleFileTypes();
+	}
 
-	// Add the filetype
-	FileTypePatterns patterns = GlobalFiletypes().getPatternsForType(_fileType);
+	// Add a final mask for All Files (*.*)
+	FileFilter wildCardFilter;
 
-	for (const auto& pattern : patterns)
+	wildCardFilter.caption = _("All Files (*.*)");
+	wildCardFilter.filter = "*.*";
+	wildCardFilter.extension = WILDCARD_EXTENSION;
+
+	_fileFilters.push_back(wildCardFilter);
+	
+	std::string wildcard = "";
+
+	for (const FileFilter& filter : _fileFilters)
 	{
-		if (!_open &&  _fileType == filetype::TYPE_MAP_EXPORT)
-		{
-			auto formats = GlobalMapFormatManager().getMapFormatList(pattern.extension);
+		wildcard += wildcard.empty() ? "" : "|";
+		wildcard += filter.caption + "|" + filter.filter;
+	}
 
-			// Pre-select take the default map format for this game type
-			map::MapFormatPtr defaultFormat = GlobalMapFormatManager().getMapFormatForGameType(
-				GlobalGameManager().currentGame()->getKeyValue("type"), pattern.extension
-			);
+	_dialog->SetWildcard(wildcard);
 
-			for (const map::MapFormatPtr& format : formats)
-			{
-				FileFilter filter;
+	for (int i = 0; i < _fileFilters.size(); ++i)
+	{
+		if (_fileFilters[i].isDefaultFilter)
+		{
+			_dialog->SetFilterIndex(i);
+			break;
+		}
+	}
+}
 
-				filter.caption = format->getMapFormatName() + " " + pattern.name + " (" + pattern.pattern + ")";
-				filter.filter = pattern.pattern;
-				filter.extension = pattern.extension;
-				filter.mapFormatName = format->getMapFormatName();
+void FileChooser::assembleMapExportFileTypes()
+{
+	FileTypePatterns patterns = GlobalFiletypes().getPatternsForType(_fileType);
 
-				_fileFilters.push_back(filter);
+	for (const auto& pattern : patterns)
+	{
+		auto formats = GlobalMapFormatManager().getMapFormatList(pattern.extension);
 
-				if (format == defaultFormat)
-				{
-					defaultFormatIdx = curFormatIdx;
-				}
+		// Pre-select take the default map format for this game type
+		auto defaultFormat = GlobalMapFormatManager().getMapFormatForGameType(
+			GlobalGameManager().currentGame()->getKeyValue("type"), pattern.extension
+		);
 
-                ++curFormatIdx;
-			}
-		}
-		else
+		for (const map::MapFormatPtr& format : formats)
 		{
 			FileFilter filter;
 
-			filter.caption = pattern.name + " (" + pattern.pattern + ")";
+			filter.caption = format->getMapFormatName() + " " + pattern.name + " (" + pattern.pattern + ")";
 			filter.filter = pattern.pattern;
 			filter.extension = pattern.extension;
-
-			// Pre-select the filter matching the default extension
-			if (pattern.extension == _defaultExt)
-			{
-				defaultFormatIdx = curFormatIdx;
-			}
+			filter.mapFormatName = format->getMapFormatName();
 
 			_fileFilters.push_back(filter);
 
-			++curFormatIdx;
+			if (format == defaultFormat)
+			{
+				filter.isDefaultFilter = true;
+			}
 		}
 	}
+}
 
-	// Add a final mask for All Files (*.*)
-	FileFilter filter;
+void FileChooser::assembleFileTypes()
+{
+	FileTypePatterns patterns = GlobalFiletypes().getPatternsForType(_fileType);
 
-	filter.caption = _("All Files (*.*)");
-	filter.filter = "*.*";
-	filter.extension = WILDCARD_EXTENSION;
+	for (const auto& pattern : patterns)
+	{
+		FileFilter filter;
 
-	_fileFilters.push_back(filter);
-	
-	std::string wildcard = "";
+		filter.caption = pattern.name + " (" + pattern.pattern + ")";
+		filter.filter = pattern.pattern;
+		filter.extension = pattern.extension;
 
-	std::for_each(_fileFilters.begin(), _fileFilters.end(), [&] (const FileFilter& filter)
-	{
-		wildcard += wildcard.empty() ? "" : "|";
-		wildcard += filter.caption + "|" + filter.filter;
-	});
+		_fileFilters.push_back(filter);
 
-	_dialog->SetWildcard(wildcard);
-	_dialog->SetFilterIndex(defaultFormatIdx);
+		// Pre-select the filter matching the default extension
+		if (pattern.extension == _defaultExt)
+		{
+			filter.isDefaultFilter = true;
+		}
+	}
 }
 
 long FileChooser::getStyle(bool open)
@@ -221,10 +236,9 @@ std::string FileChooser::getSelectedFileName()
 	if (!_open											// save operation
 	    && !fileName.empty() 							// valid filename
 	    && !_defaultExt.empty()							// non-empty default extension
-		&& os::getExtension(fileName).empty()			// no extension selected by the user
-	    && !string::iends_with(fileName, _defaultExt)) // no default extension
+		&& os::getExtension(fileName).empty())			// no extension selected by the user
 	{
-		fileName.append(_defaultExt);
+		fileName.append("." + _defaultExt);
 	}
 
 	return fileName;
diff --git a/libs/wxutil/FileChooser.h b/libs/wxutil/FileChooser.h
index 4d09a6ceb2..f218cb3b0f 100644
--- a/libs/wxutil/FileChooser.h
+++ b/libs/wxutil/FileChooser.h
@@ -34,6 +34,11 @@ class FileChooser :
 		std::string filter;		// "*.map"
 		std::string extension;		// "map"
 		std::string mapFormatName;
+		bool isDefaultFilter;			// should be selected when dialog is shown
+
+		FileFilter() :
+			isDefaultFilter(false)
+		{}
 	};
 
 	std::vector<FileFilter> _fileFilters;
@@ -111,6 +116,9 @@ class FileChooser :
 	void selectFilterIndexFromFilename(const std::string& filename);
 
 	void construct(); // shared constructor stuff
+
+	void assembleMapExportFileTypes();
+	void assembleFileTypes();
 };
 
 } // namespace wxutil
diff --git a/radiant/map/MapFileManager.cpp b/radiant/map/MapFileManager.cpp
index 644d262f8e..2a174eb2b5 100644
--- a/radiant/map/MapFileManager.cpp
+++ b/radiant/map/MapFileManager.cpp
@@ -32,8 +32,8 @@ void MapFileManager::registerFileTypes()
 	GlobalFiletypes().registerPattern(filetype::TYPE_MAP, FileTypePattern(_("Map"), "map", "*.map"));
 	GlobalFiletypes().registerPattern(filetype::TYPE_MAP, FileTypePattern(_("Portable Map"), "mapx", "*.mapx"));
 	GlobalFiletypes().registerPattern(filetype::TYPE_REGION, FileTypePattern(_("Region"), "reg", "*.reg"));
-	GlobalFiletypes().registerPattern(filetype::TYPE_PREFAB, FileTypePattern(_("Prefab"), "pfb", "*.pfb"));
 	GlobalFiletypes().registerPattern(filetype::TYPE_PREFAB, FileTypePattern(_("Portable Prefab"), "pfbx", "*.pfbx"));
+	GlobalFiletypes().registerPattern(filetype::TYPE_PREFAB, FileTypePattern(_("Prefab"), "pfb", "*.pfb"));
 
 	GlobalFiletypes().registerPattern(filetype::TYPE_MAP_EXPORT, FileTypePattern(_("Map"), "map", "*.map"));
 	GlobalFiletypes().registerPattern(filetype::TYPE_MAP_EXPORT, FileTypePattern(_("Map"), "mapx", "*.mapx"));
@@ -60,7 +60,7 @@ MapFileSelection MapFileManager::selectFile(bool open,
 
 	if (!patterns.empty())
 	{
-		defaultExt = "." + patterns.begin()->extension; // ".map"
+		defaultExt = patterns.begin()->extension; // "map"
 	}
 
 	// Display a file chooser dialog to get a new path