Hi.
I found interesting bug.
In my BP script I using Ctrl+Z key combination. When game started from Perspective view - in-game catching of Ctrl+Z key combination works good. But if I start game from Start button, located in BP Editor and in game press Ctrl+Z key combination - game and UE Editor hungs’.
Why it hungs on Ctrl+Z press?
[Video how to reproduce][1]
https://www./watch?v=gDucOEeWWHg
Hey ,
I have tried the combination that’s in your video and did not receive any type of lag or hang up in the editor. How often does this occur for you? What are your computer specifications? Are you using the source or binary version of the editor? Which preview in 4.8 are you in, 4.8.0 Preview 4 is what I tested.
Looking forward to hearing back from you, thanks!
Hi, !
I use UE4.8 P4 binary version.
My PC is: 8GB RAM, Core i7, GT 740 M.
Now I’ve created blank project to test this bug and I see, that PC hungs for a moment, but after that works perfectly… May be size of my project is issue of the hung in my project…
I got this issue about 4-5 times… But now I can’t reproduce this bug…
But, I found another “bug”! 
I can reproduce it now…
When game started from BP Editor and when Ctrl+Z pressed in game, Ctrl+Z passed to the game and to the BP editor. As result - Ctrl+Z applied to the BP script… [Video how to reproduce…][1]… May be it was root of the my issue - may be when Ctrl+Z pressed, UE tried to re-compile BP and it hungs my weak computer?
Theoretically, when I press Ctrl+Z in game, I don’t expect, that Ctrl+Z will be passed to the BP editor, what runs in background…
Hey,
I am in 4.8.0 Preview 4 currently. I have spammed control + z over and over again, from playing within the editor, as well as playing from the blueprint editor. I have not experienced any type of lag or crash within the editor. There is a crash that occurs from control + z in 4.7.6, but not in 4.8.0 Preview 4.
There is a possibility that due to your computer specifications, you may be experiencing some performance loss. Do you have another computer that you’re able to test this theory on by any ?
I appreciate your assistance, thank you!
Now I haven’t another PC…
, what about
***But, I found another “bug”! I can reproduce it now…
When game started from BP Editor and when Ctrl+Z pressed in game, Ctrl+Z passed to the game and to the BP editor. As result - Ctrl+Z applied to the BP script… [Video how to reproduce…][1] May be it was root of the my issue - may be when Ctrl+Z pressed, UE tried to re-compile BP and it hungs my weak computer?
Theoretically, when I press Ctrl+Z in game, I don’t expect, that Ctrl+Z will be passed to the BP editor, what runs in background…***
?
Thank you very much!
Hey ,
I have submitted a report referenced as: UE-16739. This report is informing our developers that while pressing play from within the blueprint editor, you can actually still revert any changes by using control z, which deletes progress in your blueprint.
I appreciate you providing us with this bug today. If you have any further questions, please let us know. Have a wonderful day. 
Thank you!