Read the Release Notes for Flash Player 26 in the link below:

Welcome to the Flash Player and AIR 26 release notes!

June 16, 2017

In today's release, we've updated Flash Player to address a bug that was impacting some Flash content. If you are having problems interacting with mouse button presses or drag and drop actions, we recommend you update to today's release.

https://helpx.adobe.com/flash-player/release-note/fp_26_air_26_release_notes.html

For those experiencing the problem, it's recommended to update your version of Flash to 26.0.0.131 using the procedures in the earlier Security Bulletin. At this time, I don't see an update released for Internet 8.1/10 for IE or Edge, but the Firefox plugin is available and so is the Flash installer for IE on Windows 7.

Hope this helps.

Grif