SUMMARY When you drag the cursor to the edge of the screen while holding a window, a rectangle behind the window appears to indicate where the window will be moved to. If you choose not to tile the window and move the cursor away from the edge then the window flashes or the indicator rectangle moves in front which seems undesirable (every other DE I've used doesn't flash). STEPS TO REPRODUCE 1. Drag window to edge to tile 2. Don't release and drag away from the edge SOFTWARE/OS VERSIONS Kubuntu 18.10 KDE Plasma 5.13.5
What exactly do you mean with "flashes"?
*** This bug has been marked as a duplicate of bug 354741 ***