This is either a bug in Construct 2 or a problem in a third party plugin or behaviour - please report it to the developer!
Everything goes right it the WebGL option is enabled.
I?m not using any third party plugin or behaviour.
EDIT: I forget it, sorry, the system specs:
- Ati HD 6990 4GB (tested with 12.10 and 12.11 Beta drivers)
- Windows 8 64bit
- Last chrome version