Steps to reproduce:
1. Load up Steam
2. Load up Construct 2 Beta 117
3. Wait 17 mins
Editor goes from silky smooth to impossible to operate.
Internet Explorer: yes/no
Operating system & service pack:
Windows 7, Windows 8
Construct 2 version:
Beta 117 (Steam)
It happens if you have steam in offline mode too, it is perfect until 17 minutes after launch, then it suddenly becomes unusable until you quit and reload.
If you load up construct 2 work for 15 mins, quit, reload construct 2, work for 15, quit.. reapeat it will be fine, but once it goes past 17 minutes, the bug occurs.
Also you can't quit steam sometimes after the bug comes up, claiming that Construct 2 is still running "Waiting for construct 2 personal to shut down".. despite quitting it and nothing present in the task manager.
[Non Steam Version Works Fine]
I should note that I have tried the stand alone beta version of 117 and it has no problems, even after an hour or so of use, so I think the problem is only with the steam version of Construct 2, or steam is interfering with it in some way.