excel4groupshare plugin: Serious issue when leaving this plugin enabled in Excel

Hi there,

there seems to be a serious issue with the "excel4groupshare plugin" that needs to be looked after by the SDL Community Developpers.

If I install this plugin and I leave it enabled and use the Microsoft Excel application for other tasks, the "Confirm Save" dialog that should appear automatically when trying to close an Excel spreadsheet that has beed edited without saving, will not appear, so in a worst-case scenario you might lose hours of work done in Excel, because you left this Excel plugin enabled after use.

I think this should be fixed, or otherwise the plugin should be taken down from the AppStore website.