Preserve font size on changing font family of selection.

This task was completed during GCI 2012
Fixes #6453

Signed-off-by: Siarzhuk Zharski <zharik@gmx.li>

src/apps/stylededit/StyledEditWindow.cpp

@@ -1599,7 +1599,20 @@ StyledEditWindow::_SetFontStyle(const char* fontFamily, const char* fontStyle)
 
 	font.SetFace(face);
 
-	fTextView->SetFontAndColor(&font);
+	int32 start = 0, finish = 0;
+	fTextView->GetSelection(&start, &finish);
+
+	if (start != finish) {
+		text_run_array* runArray = fTextView->RunArray(start, finish);;
+
+		for (int i = 0; i < runArray->count; i++) {
+			runArray->runs[i].font.SetFamilyAndStyle(fontFamily, fontStyle);
+			runArray->runs[i].font.SetFace(face);
+		}
+
+		fTextView->SetRunArray(start, finish, runArray);
+	} else
+		fTextView->SetFontAndColor(&font);
 
 	BMenuItem* superItem;
 	superItem = fFontMenu->FindItem(fontFamily);