I feel quite silly coming to ask about a Hammer issue when I should know how to fix it.
In ANY level that has stuff in it. Even dev levels that are full playable layouts. I get an issue where selecting an object will stall Hammer for about 1-3 seconds, depending on how annoying Hammer is feeling.
Here is the glitch: https://www.dropbox.com/s/5kku2crx7nc9982/20150105_012317.mp4?dl=0
I hold down the forward key so you can see that it skips once I click and then jolts forward.
I'm on Windows 8.1 with an AMD R9 290x video card. I've had some kind people test this on Windows 7 with Nvidia cards and they DON'T have this issue.
If anyone with Nvidia on 8/8.1 OR AMD on 7 can test this, I would be super grateful to you.
If anyone else has any suggestions please let me know.
What I've done.
Update video drivers
Roll back video drivers
EDIT: changed video to better show issue.