--- a/src/basegui.cpp
+++ b/src/basegui.cpp
@@ -5262,6 +5262,8 @@ void BaseGui::gotCurrentTime(double sec)
 void BaseGui::changeSizeFactor(int factor) {
 	// If fullscreen, don't resize!
 	if (pref->fullscreen) return;
+	if (isMaximized())
+		return;
 
 	if (!pref->use_mplayer_window) {
 		pref->size_factor = factor;