Than why doesn't it happen when i close Cosmos? Can you explain this?
Do you have Cosmos open on different monitor than 3ds Max? Do you have different scaling on both monitors?
If you take any 3ds Max dialog (for example "Render Setup") and move it to another monitor with different scaling, you will get the same issue.
I am guessing both 3ds Max and Cosmos use the same UI framework and it glitches in the same way.
Same Problem here, Viewport super laggy when Cosmos Browser is open.
Corona_Render_12_Hotfix_01 was fine. Now Corona_Render_12_Update_01 is having problems. How can this be a 3ds Max issue?
3ds Max issue is "UI items appear in wrong places/wrong scale", not "viewport laggy when using Cosmos".
Regarding the laggy viewport - what is your CPU model? Is this happening in any scene? (even empty?)