TileMap button does not appear when TileMap is first clicked, if a custom plugin handles it

[KoBeWi]

Godot version

4.0 rc2

System information

Windows 10 x64

Issue description

Likely caused by #71770 and follow-ups

godot_ByPZdMw3oX.mp4

I have a plugin that handles TileMaps. When I first click a TileMap, the TileMap editor does not appear (likely due to my plugin). Subsequent clicks show the editor properly.

It did not happen before. Might apply to other plugins.
It's a minor regression though and I'm opening it mostly to keep track.

Steps to reproduce

1. Have a plugin that _handles() TileMap
2. Click TileMap
3. No TileMaps appear at the bottom
4. Deselect TileMap
5. Click it again

Minimal reproduction project

TileMapPluginBug.zip

[akien-mga]

Fixed by #74039.