Since I could notice and until Flash FXP beta 1175 this bug is present.
When the OS font DPI is increased from 96 DPI to 120 DPI (mainly because of high screen resolutions) 1920x1200 FlashFXP will not resize the separator bar thus it doesnt disply the font correctly but cut.
Please referr to screenie of issue.
Hopefully this will be easy fixed.