How can I refuse active document change in MDI ?

[Sonny Aman]

Hello All, Help needed !! Situation: In and MDI application several child window are open. On the event of selecting a child window ,some task is done on the selected document,previously active document and background. Prob: Let window A,B,C and D are open, A is currently selected and doing some work. Now I want refuse selecting any other( or only B ) window before A is finished. Or may be one toolbar button is pressed, so i want to refuse any other window ( or any particular windo )to get selected. If it is possible may plz have a guide line ? Thank you.

'life is like a ten speed bike,most of us having gears we ne never use' ... i want to try those.