Thanks for your report. However we won't fix this as this is the intended behavior for that use case.
The overlay placement is adjusting for docked overlays when the overlay size changes. However, for floating overlays (no attached to a corner of the view), changing the overlay size makes it goes outside of the view until someone click on the title bar to move it.
The reason is that we don't want to unexpectedly move the entire overlay away from the mouse and its current action area.
I hope you understand that reason as well :)
Thanks a lot!