DO-NOT-MERGE-FOR-TESTING: Remove hard-coded button styling in workspace selection dialog

[vogella]

Summary

Test PR for #3905.

The workspace selection dialog at IDE startup mimics dark-theme styling because the ThemeEngine is not yet available. On macOS this produces buttons that look different from the buttons on other dialogs (e.g. File > Switch Workspace).

This change skips the hard-coded dark styling for Button controls only, so they get the native macOS dark appearance. All other widgets (Shell, Composite, Label, Link, ExpandableComposite) continue to be styled as before.

Test plan

• Start the IDE with a dark theme on macOS and confirm the workspace selection dialog buttons match the buttons in File > Switch Workspace.
• Start the IDE with a light theme and confirm nothing changed.
• Confirm the rest of the workspace selection dialog (background, labels, links, expandable settings section) still looks correct in dark mode.

[github-actions]

Test Results

   852 files  ±0     852 suites  ±0   57m 46s ⏱️ + 4m 4s
 7 911 tests ±0   7 668 ✅ ±0  243 💤 ±0  0 ❌ ±0 
20 235 runs  ±0  19 580 ✅ ±0  655 💤 ±0  0 ❌ ±0 

Results for commit 36d6113. ± Comparison against base commit 1cbae34.

[vogella]

@BeckerWdf can you test this?

[BeckerWdf]

@BeckerWdf can you test this?

Didn't I already last week?

[vogella]

@BeckerWdf can you test this?

Didn't I already last week?

This one is for your remark here: #3905 (comment) and AFAICS you did not give me feedback on this PR (which might solve your button styling).

[BeckerWdf]

Ah sorry. I did test it. This PR solves it. Somehow I did not write that last week.

[vogella]

Ah sorry. I did test it. This PR solves it. Somehow I did not write that last week.

Can you post a screenshot, please?

[BeckerWdf]

With your change:

Without your change:

[vogella]

With your change:

Without your change:

That looks like the same to me? The new one is better? Can you explain why?

[BeckerWdf]

With your change:
Without your change:

That looks like the same to me? The new one is better? Can you explain why?

Look at the buttons. They are very different. The first one is correct (as all buttons in the IDE look this way). The second one is wrong. I already highlighted the difference in #3905 (comment).

[vogella]

I assume you expected a blue button like in the original example you posted. If the above is sufficient I start testing it on Linux and Windows. Windows testing usually takes a bit longer for me.

[BeckerWdf]

I assume you expected a blue button like in the original example you posted. If the above is sufficient I start testing it on Linux and Windows. Windows testing usually takes a bit longer for me.

Sure. Having the button also in blue would be even better. But already this one is fetter then this strange "gradient" styled buttons.

[vogella]

Linux Dark looks also really good:

Linux Light (unchanged to last years release):