I have no idea what changed from version 3.9.5.0 to the actual 4.0.0 one but I had to revert back to the old version as the v4 release is extremely unresponsive in Win8 which means it needs a lot of time to open and about 10-20s for each click I do within the UI.
Interestingly it doesn't seem to consume a lot of RAM or CPU, it's just sluggish.
Interestingly it doesn't seem to consume a lot of RAM or CPU, it's just sluggish.