statusbar: if cell overflows with center, limit x by 0

fix Alexey-T/CudaText#5671 better

fix in drag-drop to other tabs control

fix paint drop-marker when drag-dropping tab between tab-groups

tabs: fix regression in multiline-tabs

cln

fixing Alexey-T/CudaText#5630

refac in MakeVIsible

fixing Alexey-T/CudaText#5510 (comment)

tweak scrollbar theme Thumb size