Tool Bar Item Disappears after DPI Change and Enabled State Change

[runaway94]

Describe the bug
A toolbar menu item with text and icon (mode="FORCE_TEXT") disappears from the tool bar after a DPI change and the tool bar refreshes (e.g. the handler is disabled/enabled)

To Reproduce
You need a tool bar with a few tool bar items (for me there are three items) that show text and icon (mode="FORCE_TEXT").
When I move the window form a 100% scaled monitor to a higher scaled monitor (e.g. 150% scaling) the tool bar icons are still available but the label text is cut off (from "My Label" to "My La...").
As soon as any tool bar item is disabled, the label texts are written out in full again but the last tool bar item disappears from the tool bar.
This only happens if text and icon are shown and if the scaling changed, if the menu is initiated with a higher scaling everything looks fine.
The item will also not re-appear if it is enabled again.

Expected behavior
The tool bar icon should not disappear.

Screenshots
On 100% scaling

Moved to 150% scaling

After handlers are enabled

Environment:

1. Select the platform(s) on which the behavior is seen:

• • All OS
• • Windows
• • Linux
• • macOS

2. Additional OS info (e.g. OS version, Linux Desktop, etc)

3. JRE/JDK version

Version since
Eclipse or SWT version since when the behavior is seen [e.g. 4.23]

Workaround (or) Additional context
Add any other context about the problem here.
Any known workarounds for the problem?

[HeikoKlare]

Thank you for the report, @runaway94.

Since you already seem to have an example/snippet from which you have taken the screenshots, can you please share that with us so that we can easily reproduce the issue?

[runaway94]

Hi @HeikoKlare thank you for the quick answer.

Unfortunately, I’m unable to share the exact code snippets here, as they are part of a commercial application in which commands, handlers, and menu contributions are distributed across multiple plugins.

However, I created a small, self-contained example in which the same problem occurs:

<?xml version="1.0" encoding="UTF-8"?>
<plugin>

  <!-- Commands -->
  <extension point="org.eclipse.ui.commands">
    <command id="demo.command.one"   name="One"/>
    <command id="demo.command.two"   name="Two"/>
    <command id="demo.command.three" name="Three"/>
  </extension>

  <!-- Toolbar contribution (main toolbar) -->
  <extension point="org.eclipse.ui.menus">
    <menuContribution locationURI="toolbar:org.eclipse.ui.main.toolbar?after=additions">
      <command commandId="demo.command.one"  
                 label="One"
                 icon="icons/image.png"
                  mode="FORCE_TEXT"
                  style="push"/>
      <command commandId="demo.command.two"  
                 icon="icons/image.png"
                  label="Two"
                  mode="FORCE_TEXT"
                  style="push"/>
      <command commandId="demo.command.three" 
                 icon="icons/image.png"
                  label="Three"
                  mode="FORCE_TEXT"
                  style="push"/>
    </menuContribution>
  </extension>

  <!-- SourceProvider (liefert Variable threeEnabled) -->
  <extension point="org.eclipse.ui.services">
    <sourceProvider
        provider="demo.rcp.ThreeEnabledSourceProvider">
      <variable name="demo.threeEnabled"/>
    </sourceProvider>
  </extension>

  <!-- Handlers -->
  <extension point="org.eclipse.ui.handlers">
    <handler commandId="demo.command.one" class="demo.rcp.ToggleThreeHandler"/>
    <handler commandId="demo.command.two" class="demo.rcp.NoOpHandler"/>

    <handler commandId="demo.command.three" class="demo.rcp.NoOpHandler">
      <!-- disabled when demo.threeEnabled == false-->
      <enabledWhen>
        <with variable="demo.threeEnabled">
          <equals value="true"/>
        </with>
      </enabledWhen>
    </handler>
  </extension>

</plugin>

package demo.rcp;

import java.util.Collections;
import java.util.HashMap;
import java.util.Map;

import org.eclipse.ui.AbstractSourceProvider;
import org.eclipse.ui.ISources;

public class ThreeEnabledSourceProvider extends AbstractSourceProvider {

    public static final String VAR_THREE_ENABLED = "demo.threeEnabled";

    private boolean threeEnabled = true;

    @Override
    public void dispose() {

    }

    @Override
    public Map<String, Object> getCurrentState() {
        Map<String, Object> m = new HashMap<>();
        m.put(VAR_THREE_ENABLED, Boolean.valueOf(threeEnabled));
        return Collections.unmodifiableMap(m);
    }

    @Override
    public String[] getProvidedSourceNames() {
        return new String[] { VAR_THREE_ENABLED };
    }

    public boolean isThreeEnabled() {
        return threeEnabled;
    }

    public void setThreeEnabled(boolean enabled) {
        if (this.threeEnabled == enabled) return;
        this.threeEnabled = enabled;

        fireSourceChanged(ISources.WORKBENCH, VAR_THREE_ENABLED, Boolean.valueOf(this.threeEnabled));
    }
}

package demo.rcp;

import org.eclipse.core.commands.AbstractHandler;
import org.eclipse.core.commands.ExecutionEvent;
import org.eclipse.core.commands.ExecutionException;
import org.eclipse.ui.ISourceProviderService;
import org.eclipse.ui.IWorkbenchWindow;
import org.eclipse.ui.handlers.HandlerUtil;

public class ToggleThreeHandler extends AbstractHandler {

    @Override
    public Object execute(ExecutionEvent event) throws ExecutionException {
        IWorkbenchWindow win = HandlerUtil.getActiveWorkbenchWindow(event);
        if (win == null) return null;

        ISourceProviderService sps = win.getService(ISourceProviderService.class);
        if (sps == null) return null;

        ThreeEnabledSourceProvider sp =
            (ThreeEnabledSourceProvider) sps.getSourceProvider(ThreeEnabledSourceProvider.VAR_THREE_ENABLED);

        if (sp != null) {
            sp.setThreeEnabled(!sp.isThreeEnabled()); // toggle
        }
        return null;
    }
}

[HeikoKlare]

Thank you for providing the reproducer. With slight adaptations, I was able to reproduce exactly the reported issue.

The update of the items upon DPI change is obviously incomplete (the resize of the individual items is not adapted to the new image and/or font size). The DPI change processing of ToolBar is quite complicated, so it's not that easy to understand where exactly the implementation is broken. But in any case, properly updating the item's image resolves the issue for me. The existing implementation for updating the image (in the Item.handleDPIChange implementation) seems to be insufficient anyway (as it is effectively a no-op in most cases).
I have thus adapted that implementation to actually remove and reset the image, which resolves the issue for me:

• [Win32] Properly reinitialize image of items on DPI changes #3074

But I am not sure if this is something that can still make it into the 2026-03 release. The change is small but given the fact that the DPI Change processing for toolbars is so complex, I am a bit concerned that this could have an unintended side effect that we won't detect until the release anymore.

[runaway94]

Hi @HeikoKlare
Thank you for looking into this issue.

For our product, it is not essential that the bug be fixed in the next release. We have identified a workaround that avoids disabling the handler altogether. The minor layout shift is acceptable as long as the items remain visible and usable.

It would be sufficient for us if the fix is included in a future release, once it has been thoroughly tested.