Reduce clutter in toolbar

[FliegendeWurst]

View menu:

This reduces clutter in the main toolbar by:

• moving the action history next to the other undo buttons
• moving the layout controls to a menu (View -> Layout)
• marking the exploration extension as experimental (as documented)
• disabling the functionality to reorder toolbars (only ever used by accident)

As a bonus, the bug that extension panels sometimes fail to show up should also be fixed.

[codecov]

Codecov Report

Merging #3198 (85357af) into main (f798501) will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##               main    #3198   +/-   ##
=========================================
  Coverage     37.59%   37.59%           
  Complexity    16684    16684           
=========================================
  Files          2043     2043           
  Lines        125713   125713           
  Branches      21106    21106           
=========================================
  Hits          47256    47256           
  Misses        72693    72693           
  Partials       5764     5764           

Impacted Files	Coverage Δ
.../key_project/exploration/ExplorationExtension.java	0.00% <ø> (ø)

📣 We’re building smart automated test selection to slash your CI/CD build times. Learn more

[github-actions]

Thank you for your contribution.

The test artifacts are available on Artiweb.
The newest artifact is here.

[wadoon]

This reduces clutter in the main toolbar. Other options to consider:

• moving the layout controls to a menu

Yes the layout toolbar can be moved to a menu.

[FliegendeWurst]

@WolframPfeifer I believe the bug that extension panels sometimes fail to show up is fixed with the latest commit.

[WolframPfeifer]

@WolframPfeifer I believe the bug that extension panels sometimes fail to show up is fixed with the latest commit.

I tested it by switching to an older branch without proof slicing and then back to this one, and the slicing panel appeared as expected. Thanks!

[FliegendeWurst]

Current state:

[WolframPfeifer]

I have a few final requests (see my suggestions). I would like to have the status line messages harmonized to Layout saved to ... and Layout loaded from ....

Otherwise, I think the PR is fine and really increases usability of KeY.

[FliegendeWurst]

I have integrated all of your suggestions.

[WolframPfeifer]

Thanks!