Unfocused project browser has no tooltips for footer buttons

[peter-b]

When the project browser doesn't have focus, the buttons in the footer don't have tooltips.

Steps to reproduce:

1. Open the project browser
2. Focus the project browser
3. Mouse over the footer buttons and note that tooltips appear
4. Create a new stack
5. Focus the new stack
6. Mouse over the project browser's footer buttons and note that tooltips are absent.

[runrevelanor]

This seems to be related to the paletteActions widget rather than the Project Browser stack.

[livecodealice]

Issue still present in 8.1.6