I can run G(ame) just fine in the main window, but I have never seen a game preview window for Blueprint when game simulation is active. I am sorry if this is a common question, but I have looked for more than an hour high and low for some other similar problem discussion.
How can I make the 3d preview window appear ?
UE 5.0.3
Windows 11
RTX3080
Core i9
32G
Latest Studio Drivers (updated this morning)
Thank you for reading
Hey ImagineThatCGI! Welcome to the forums!
So in this window, you are simulating, and the blueprint is working actively. If you want to see the game, you need to go over to the “GameMap0” tab there. And if you open up the viewport it will give an active view of your character, whatever it’s doing. You may want to drag that tab out to make another window if you’re going to test while watching the blueprint simultaneously. Or did I misunderstand your question?
Let us know! 
Thank you so much for your suggestion.
I did try this many times but it will not allow me to drag down the GameMap0 tab. I can drag (left mouse) it left or right along the top bar of tabs. It will not release the window from the tab bar. Center mouse does not affect it. Right mouse on it gives options to close other windows.
Is there some shortcut command maybe that will let me release the GameMap0 tab from the tab bar ?
I am very new to UE5,(3 days), so I VERY much appreciate your efforts to help me figure this out.
Thank you kindly
In a further effort to find a solution I have put my original project aside and created a very minimal Debug project. The Debug project consists only of a blank project and the ThirdPersonCharacter content. I can run or stop the game. I can see the blueprint active or inactive. I can dock and undock the blueprint window. I cannot undock the tab called Minimal_Default by any dragging action on the tab.
I really think that I will need a preview window of the game action overlayed with the blueprint to proceed further with development of the character actions and I am super keen to move forward but alas I am stuck at this point.
Any further suggestions for how to undock or preview the game activity 3D window would be greatly appreciated
Thank you very much
After a lot of trial and error and a good bit of reading I have found the solution to my dilemma. It is not related to the Level Editor tab or dragging the Level Editor tab.
The issue is described in great detail here :
In-Editor Testing (Play & Simulate) in Unreal Engine | Unreal Engine 5.0 Documentation
In a nutshell my little game start/stop commands where stuck in “Simulate” mode and that prevented the PIP from popping up when I clicked start in the Blueprint window. All I had to do was change the setting to “Selected Viewport” and everything worked perfectly after that.
The setting causing me all the grief is fixed on this pulldown shown below. I suppose I probably accidently hit Alt-S at somepoint and had accidently switched it to Simulate. Ooops !!
Again, thank you kindly for taking the time to read and suggest alternatives.
This problem can be considered closed.
Hey again @ImagineThatCGI! So that window (Minimal Default) is the MAIN window of UE5. You cannot undock it as it is your home screen, more or less. You would undock the BP_ThirdPersonCharacter. Now you can click the 3 dots there next to Pause, Step, Play, and Eject to change what mode you want to try things out in. However, a lot of the testing functionality is lost if you Play in Window vs PIE (Play In Editor).
In essence, you can’t undock the main tab as it’s the beating heart. But you could pull out any OTHER tabs and make as many windows as you need. Hope that helped explain things a bit better!
Edit: It looks like you figured it out! Go you!
Thanks! Being new to UE5, even I faced the same issue and this helped
