diff --git a/src/core/contexts/cocoawindowcontext.mm b/src/core/contexts/cocoawindowcontext.mm
index 857a92f..6d70409 100644
--- a/src/core/contexts/cocoawindowcontext.mm
+++ b/src/core/contexts/cocoawindowcontext.mm
@@ -601,6 +601,9 @@ void setSystemTitleBarVisible(const bool visible) {
                 
                 NSMutableArray<NSButton *> *array = [NSMutableArray arrayWithCapacity:3];
                 for (NSButton *button : self_->systemButtons()) {
+                    if (!button) {
+                        continue;
+                    }
                     button.hidden = !self_->systemButtonVisible;
                     [array addObject:button];
                 }