Several users have been reporting the game getting slow or having display issues with mouse clicks. Unfortunately this issue has also been reported not only in our game but in other games and has been happening since last flashplayer updates.
Here are some suggestions that we gathered from adobe official website which should help:
[...] If you have display problems with Flash Player, such as poor picture quality or slow display times, deselect Enable Hardware Acceleration in the Display panel. This should eliminate hardware or driver compatibility problems with Flash Player. Flash Player then uses software to scale and display the content.[...]
More information can be found there:http://www.macromedia.com/support/documentation/en/flashplayer/help/help01.html
We also suggest you to try and change your browser to Firefox, Microsoft Edge or Opera, as several players also have been reporting that changing to these browsers have helped them improving the situation. If possible, you can also try to remove your Flash Player and download an older version.
In the meantime we have contacted Flash Player about these issues and are doing everything we can on our part to fix these issues as fast as possible. We are very sorry for all the inconveniences this has caused.