Dock Window Screen Markers move around with the window being dragged

[andrei-lz]

Reproducible Steps:

1. Run WalnutApp Example
2. Click and drag on a floating window
3. Drag that window over one of the dockspace markers
4. The marker that's drawn on top of the dragged window will now lag and move in the direction that the window is being dragged while continuously snapping back to their normal place

From a user perspective, I don't necessarily think it should be drawn on top although I understand the choice to do that. I believe they should maybe be half transparent as it is a bit jarring.

Here's a demonstration of the glitch:

https://youtu.be/ZHxc23C_cNU