Fix: Read filter selection directly from panel's accessory view

The previous fix relied on the cached popup instance variable, which may
not be accessible or may have stale state in the delegate callback context.

Now we read the filter selection directly from the panel's accessory view
at the time the delegate method is called, ensuring we get the current
selection that the user actually chose.

This should fix the issue where the wrong extension (abcd instead of png)
was still being appended even after the previous fix.

Co-authored-by: vogella <[email protected]>

Author: Copilot

bundles/org.eclipse.swt/Eclipse SWT/cocoa/org/eclipse/swt/widgets/FileDialog.java

@@ -536,8 +536,39 @@ long panel_userEnteredFilename_confirmed (long id, long sel, long sender, long f
 	 * On newer macOS versions (Sequoia/Tahoe), the filter selection change callback
 	 * may not be called before this method, so we need to update selectedExtension
 	 * based on the current popup selection to ensure we append the correct extension.
+	 * 
+	 * We need to get the popup from the panel's accessory view rather than using
+	 * the cached instance variable, as the delegate callback may have a different context.
 	 */
-	getSelectedExtensions();
+	NSView accessoryView = panel.accessoryView();
+	if (accessoryView != null && accessoryView.isKindOfClass(OS.class_NSPopUpButton)) {
+		NSPopUpButton currentPopup = new NSPopUpButton(accessoryView.id);
+		int currentFilterIndex = (int)currentPopup.indexOfSelectedItem();
+		if (filterExtensions != null && 0 <= currentFilterIndex && currentFilterIndex < filterExtensions.length) {
+			String exts = filterExtensions[currentFilterIndex];
+			int index = exts.indexOf(EXTENSION_SEPARATOR);
+			String[] extensions = index != -1 ? exts.split(";") : new String[] {exts};
+			if (extensions.length > 0) {
+				String ext = extensions[0];
+				String filter = ext.trim();
+				if (!filter.equals("*") && !filter.equals("*.*")) {
+					if (filter.startsWith("*.")) {
+						filter = filter.substring(2);
+					} else if (filter.startsWith(".")) {
+						filter = filter.substring(1);
+					}
+					// Handle multi-part extensions
+					int i = filter.lastIndexOf(".");
+					if (i != -1 && ((i + 1) < filter.length())) {
+						filter = filter.substring(i + 1);
+					}
+					selectedExtension = filter;
+				} else {
+					selectedExtension = null;
+				}
+			}
+		}
+	}
 	NSString filenameWithExtension = new NSString(filename);
 	filenameWithExtension = appendSelectedExtension(filenameWithExtension);
 	return filenameWithExtension.id;