Shell Icon disappears on zoom change

[ShahzaibIbrahim]

Setting an image for a shell on top left disappears on monitor change in monitor specific scaling mode. The reason behind it was that the image was being disposed by setImages method called after setImage in handleDPIChanged. The setImages method should not have been called if there are no images present in the array. The solution is to check whether we have any images in the in the array with the null check.

How to Reproduce

• Run the following snippet with the following arguments

  -Dswt.autoScale.updateOnRuntime=true
  -Dswt.autoScale=quarter
  

 Display display = new Display();
 Image image1 = display.getSystemImage(SWT.ICON_WORKING);
 Shell shell = new Shell(display);
 shell.setText("My Snippet");
 shell.setImage(image1);
 shell.open();
 while (!shell.isDisposed()) {
     if (!display.readAndDispatch()) {
   	  display.sleep();
     }
 }
 display.dispose();

• Move the shell from one monitor to another (with different zoom levels)
• The icon on top left of the shell will disappear

Expected Result

The icon on top left should remain intact after the zoom change

[github-actions]

Test Results

   502 files  ±0     502 suites  ±0   10m 9s ⏱️ - 1m 4s
 4 334 tests ±0   4 320 ✅ ±0   14 💤 ±0  0 ❌ ±0 
16 575 runs  ±0  16 466 ✅ ±0  109 💤 ±0  0 ❌ ±0 

Results for commit 10745e4. ± Comparison against base commit 12e0564.

♻️ This comment has been updated with latest results.