[CyanVoxel]

Note

This PR is targeting the dev branch for release with Alpha v9.7.

Summary

(Builds off of #1539 + #1540 + #1541 + #1542) This PR adds box selection to the thumbnail grid. The selection is not finalized until you let go of the mouse, mimicing macOS Finder behavior and preventing rapid updates in the Inspector (just generally the behavior I prefer).

• Clicking and dragging on the background will reset the current selection and only select the items in the box when let go
• Holding Shift while clicking and dragging will add to the current selection when let go
• Holding Ctrl/Command while clicking and dragging will invert the selection under the box

NOTE: Padding between thumbnails was increased to make it easier to start box selections, but the Inspector's default size has not been updated to compensate. I'll be addressing this in a followup PR that focuses on deeper areas of the Inspector's sizing behavior and splitter styling.

Tasks Completed

• Platforms Tested:
  • Windows x86
  • Windows ARM
  • macOS x86
  • macOS ARM
  • Linux x86
  • Linux ARM
• Tested For:
  • Basic functionality
  • PyInstaller executable