Spacebar doesn't work on first drag after clicking on other elements

[RogerLevy]

Describe the bug

Buggy spacebar detection leads to constant editing mistakes.

Steps to reproduce

1. Open/Create a map with several layers
2. Edit a layer, pan around with spacebar
3. Select a different layer
4. Hold spacebar and try to pan the tilemap. It will use the current tool instead of panning. Try again and it works the second time.

Expected behavior

Tiled should be detecting the spacebar at a global level, so that the first time you click in the editing area while holdign it, the view will pan as expected.

OS version

Windows 10

Tiled version

1.11.2