Steps to reproduce:
1. Set Focus Policy to "Focus Follows Mouse"
2. Activate "Raise, with the following Delay"
3. Activate SlideBack effect
4. Move the mouse to pass focus and raise windows

Actual result:
Slideback effect does not kick in. Only when explicitly change by e.g. Task bar

Expected result:
once the stacking order changes the effect kicks in.

Reason for behavior:
SlideBack reacts on activation changes and at that time the stacking order has not yet been updated. Changes to the stacking order are not provided to the effect system.