Bug 574112 - [GTK4] Fix incorrect widget destruction due to removal of

GtkContainer

- Override Control's destroyWidget to correctly remove widget from
parent SWTFixed container
- Removed unused function (which wraps a call to destroyWidge)
destroyHandle in Scrollbar
- Remove comment in Scrollbar's destroyWidget override which has been
there since 2009 or later, clearly not required to be uncommented

Change-Id: Iae93ded9d80e8f5be7716add490f1bd8f216f573
Signed-off-by: Paul D'Pong <sdamrong@redhat.com>
Reviewed-on: https://git.eclipse.org/r/c/platform/eclipse.platform.swt/+/181737
Tested-by: Platform Bot <platform-bot@eclipse.org>
Reviewed-by: Alexander Kurtakov <akurtako@redhat.com>

2 files changed, 13 insertions, 5 deletions

diff --git a/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/Control.java b/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/Control.java
index 04aceccc0a..7b5e6c41d2 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/Control.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/Control.java
@@ -4768,6 +4768,19 @@ void releaseWidget () {
 	}
 }
 
+@Override
+void destroyWidget() {
+	if (GTK.GTK4) {
+		// Remove widget from hierarchy  by removing it from parent container
+		if (parent != null) {
+			OS.swt_fixed_remove(parent.parentingHandle(), fixedHandle);
+		}
+		releaseHandle();
+	} else {
+		super.destroyWidget();
+	}
+}
+
 /**
  * GTK3 only, do not call on GTK4.
  * @param window a GdkWindow
diff --git a/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/ScrollBar.java b/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/ScrollBar.java
index 538c23e621..187e2bfa61 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/ScrollBar.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/ScrollBar.java
@@ -157,15 +157,10 @@ void deregister () {
 	if (adjustmentHandle != 0) display.removeWidget (adjustmentHandle);
 }
 
-void destroyHandle () {
-	super.destroyWidget ();
-}
-
 @Override
 void destroyWidget () {
 	parent.destroyScrollBar (this);
 	releaseHandle ();
-	//parent.sendEvent (SWT.Resize);
 }
 
 /**