ATTabs on gtk2 and win32 paints nice, all tabs borders are sharp.
ATTabs on qt5 looks bad-- pic shows very ugly borders of tabs.
Zeljko, do you need very simple demo or you know the problem?
(it's hard to make demo.)
Lazarus 2.1.0 r64940 FPC 3.2.1 x86_64-linux-gtk2