Mdi Child tabbing problem

Hi guyz,

frm_main : mdiform
child : 10 x child of frm_main which has some objects covers whole form

windowstate property is maximized for each child forms.

when i open 1rst child there is no problem

when i open 2nd after 1rst form i see some leftover on the screen. :(

same story for others after 1rst.

If child form is already loaded at least one time i'm using child.zorder 0 command for tabbing these forms.

i've tried child.avtivate also but result is same.

when i use CTRL+TAB combination there is no leftover on screen :cool: (but i've no chance to choose which form to tab, they are being actived in turn :mad:)

How i can open and tab childforms without leftover on screen?

You can see what i'm talking about here on right top of grey area on video : http://youtu.be/wfznBuXWueA