Although there is no sure way for filePro to prevent closing a Window without properly exiting filePro, if you run filePro in FullScreen mode rather than in a Window, the "Exit" option is not available to the user unless the user switches from FullScreen mode back to a window. Although we don't normally recommend running filePro in FullScreen mode, this should solve your problem. To run in FullScreen mode, change your Icon Options properties by checking "Full Screen" in the display options.
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