From the image could be seen how the flowlayoutpanel leaves blank space between the categories in my menu even though the margins of all panels are set to 0 including the flowlayoutpanel also all labels and buttons margins are set to 0
Managed to fix my problem by implementing it without flowlayoutpanel by using timers :)
I'll leave the question open if somebody knows how to fix the flowlayoutpanel situation