Problems with ADXTaskPane are solved in Add-in Express for Office v.9
Recently, our mail boxes became overwhelmed with a flow of reports describing how Add-in Express panes appear outside the host application’s window. This is a manifestation of how the code calling the SetParent Windows API function can be incompatible with the recent Windows API change supported by Office 2016: Microsoft introduced DPI contexts and related API functions to let you get/set the current context. Now, to call SetParent, you must set the DPI context corresponding to the DPI context of the target window. Version 8 of Add-in Express for Office (.net and VCL) doesn’t set the required DPI context when embedding your ADXTaskPane in the hosts’ windows and this is the direct cause of the issue. Affected are the Add-in Express 8 based add-ins running in Office 2016 on Windows 10.
A workaround is to choose the Optimize for compatibility option in Display Settings; see the status bar or File | Options | General. Select this option, restart the Office application and it will use the old Windows API. If Display Settings is missing, the only way for you is to switch to Add-in Express 9.
ADX.NET 9 and ADX.VCL 9 introduced only one feature: support for the Windows API changes above. You may be required to modify your code as we described in Add-in Express adds support for multiple monitors in Office.
Below is a download link for an installer of a sample add-in that demonstrates how an add-in based on Add-in Express 9 behaves in Excel, Word, PowerPoint and Outlook from Office 2000-2016.
This sample add-in was developed using version 9.1 of Add-in Express for Office and .net: