Selections are not highlighted blue

[matterhorn103]

Avogadro version: (please complete the following information from the About box):

• Avogadrolibs: 1.100.0 (commit 88ff1a7)
• Qt: 6.8.3
• Occurs with Flatpak (beta) and AppImage (nightly)!

Desktop version: (please complete the following information):

• OS: Linux
• Version: openSUSE Tumbleweed 20250405

Describe the bug

On current builds, the current selection is not indicated visually with the usual translucent blue spheres.

The Selection Tool does seem to work as normal, however. For example, selecting a methyl group with the marquee and then moving it with the Manipulation Tool does what is expected, the Manipulation Tool moves the whole molecule after using Ctrl+A, etc. There is just no visual marker of selection status.

The behaviour emerged sometime between 432e1ce and 88ff1a7; I'm guessing it was a side-effect of #1983.