Desktop Debug Tools: Combine and improve children list and Display Object Picker

[n0samu]

The Display Object Picker and Children tab of Ruffle's Debug Tools serve a similar purpose, like the Elements tab in a browser's Developer Tools. But Ruffle's implementation is a bit disjointed and confusing - here are some suggestions to improve it:

• Make the Display Object picker a button on the Children tab, instead of being its own window. Its option checkboxes can go next to it; they can be above or below the Search box.
  • We could still have a Search Display Objects button on the Debug Tools menu; it would just open up the Children tab of the Stage Info and automatically activate the picker mode.
• Instead of hiding some of the display objects in the tree, clicking to finish searching should highlight the innermost display object in the tree matching the mouse position, just like clicking an element in the browser developer tools' element picker. For example, the text could be displayed in bold.
  • It may also be helpful to automatically collapse parts of the tree not matching the current search/position, but I'm not totally sure.
  • Alternatively, the selected object should be scrolled into view in the tree, if possible.
• When the Display Object Picker is activated from the Children tab of a movieclip, picking could be restricted to the children of that specific movieclip.
• In the display object tree, movieclips with no children should not have a button next to them to expand/collapse their subtree. That would make manually searching through some movies' trees much faster and easier. (Some games have lots of empty movieclips for whatever reason.)
• Every display object shown in the Children tab (display object tree) should have a color displayed next to it, as the Display Object Picker is currently. But that color should be the actual color of that display object's debug rect. Changing the debug rect's color should update the color displayed next to the object on the Children tab. And when hovering over the object in the tree, the highlight box's color should be the same as its debug rect color! Since the highlight box is thicker than the normal debug rect, it will still be noticeable when the debug rect is also active.
  • My point is that every display object should have one debug/highlight color that is consistent at all times. This would make it so much easier to keep track of what I am looking at.

[n0samu]

In the display object tree, movieclips with no children should not have a button next to them to expand/collapse their subtree.

This has been implemented in #14963!