fix(dwindle): ignore fullscreen window for positioning when use_active_for_splits=false

[rszyma]

Describe your PR, what does it fix/add?

Repro Steps:

1. Use dwindle + use_active_for_splits=0
2. have 3 windows open next to each other (layed out horizontally and spaced evenly)
3. maximize the leftmost one
4. move mouse pointer near the right edge of the screen
5. open a new window (e.g. a terminal)

Actual:

The new window opens next to leftmost window.

Expected:

The new window opens next to the rightmost window - nearby where the mouse cursor is. That's what use_active_for_splits=0 should do (from wiki: "prefer mouse position for splits")

Note, that this behavor is exactly what would happen if you inserted an extra step of minimizing the fullscreen window between the steps 4 and 5. And this PR attempts to do exacly this, trying to ignore the current fullscreen window when creating a new one.

Before vs after videos

In the following videos I have also set smart_split=1, which makes the issue more pronounced. Btw on videos I'm not doing the exact steps above, sowwy about that (they are old vids), but it should be clear enough I hope.

Before:

Details

before.mp4

After:

Details

after.mp4

Is there anything you want to mention? (unchecked code, possible bugs, found problems, breaking compatibility, etc.)

It actually used to work like this before a year ago or so, and it's been annoying me for a long time. I've had enough.

Is it ready for merging, or does it need work?

should be ready to go, unless we want to make this configurable.

[vaxerski]

👍