Show mouse move control even when not showing single line

[merks]

With this simple change, the controls to do the merging still appear when you hover over the area that's connecting the changes on the two sides:

@HannesWell @akurtakov

I think this addresses your concerns about lost of functionality.

@iloveeclipse

Given there is no visual appearance until you hover, I assume this is not a controversial addition.

[github-actions]

Test Results

    54 files  ±0      54 suites  ±0   35m 48s ⏱️ -56s
 4 546 tests ±0   4 522 ✅  - 1   23 💤 ±0  1 ❌ +1 
12 234 runs  ±0  12 074 ✅  - 1  159 💤 ±0  1 ❌ +1 

For more details on these failures, see this check.

Results for commit 0e395ed. ± Comparison against base commit 8f967b6.

[HannesWell]

That's much better and looks good.
Thank you!

I tried this out and it mostly works well.

It's just that on long ranges the move buttons are hard to find without a marker.
On the other hand, showing a marker for short ranges looks like it clutters the diff.
Maybe the button marks (the small squares) can be shown only if a change exceeds a certain length.
However, this can also be done in a follow-up.

[merks]

The windows tests passed when I restarted it, so the summary is incorrect, i.e., not updated.

[merks]

FYI, I also experiment with commenting out the fUseSingleLine guard here:

eclipse.platform/team/bundles/org.eclipse.compare/compare/org/eclipse/compare/contentmergeviewer/TextMergeViewer.java

Lines 4580 to 4592 in 2222ff6

	if (fUseSingleLine && isAnySideEditable()) {
	// draw resolve state
	int cx= (w-RESOLVE_SIZE)/2;
	int cy= ((ly+lh/2) + (ry+rh/2) - RESOLVE_SIZE)/2;
	g.setBackground(fillColor);
	g.fillRectangle(cx, cy, RESOLVE_SIZE, RESOLVE_SIZE);
	g.setForeground(strokeColor);
	g.drawRectangle(cx, cy, RESOLVE_SIZE, RESOLVE_SIZE);
	}
	}
	}

It's more visual clutter but better (familiar) affordance:

I though maybe circles would look prettier... But then I thought it seemed more likely to raise objects if there visual changes.

Hopefully folks will feel motivated to make further improvements.