App minimises when closing form back to MDI

[Streetdaddy]

In my application, if you change data in the TrueGrid of certain forms and then cancel, a system msgbox informs you that you have made changes and they will not be saved if you continue with the cancel process. However, whenyou click ok to proceed with canceling and close the modal form to show the MDI behind it, the app minimises if there is a maximised app running behind it? I can set the focus back to the MDI, but the flickering from max to min and back is annoying and ugly...<br>
Has anyone else had this problem? <br>
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nb * On the MDI are some List Box controls using icons.