Press ESC when you are done with placing particular asset to get the window back 
Sometimes it hides behind things: try <alt>+<tab> until you get the asset window, then hit <esc> (even if it does not come to the front of the screen).
Sometimes it hides behind things: try <alt>+<tab> until you get the asset window, then hit <esc> (even if it does not come to the front of the screen).
i try alt + tab, and not find asset window, even i click the asset button or press ESC thousand time...omg
Yes, I also encountered this BUG
Hey mm3d.arsitektur and tas_1985 , sorry to hear about this problem. This is already filed as a dedicated bug report, but we're not yet able to reproduce this issue ourselves faithfully yet.
Is there anything "special" you're doing before this problem occurs? You can gladly elaborate the exact steps you're taking prior, this may very help us to reproduce it. Further, does a restart of SketchUp help with this at first, and then later on this issue surfaces again, or is it constantly on your machine? Maybe this occurrence is generally random?
Hey mm3d.arsitektur and tas_1985 , sorry to hear about this problem. This is already filed as a dedicated bug report, but we're not yet able to reproduce this issue ourselves faithfully yet.
Is there anything "special" you're doing before this problem occurs? You can gladly elaborate the exact steps you're taking prior, this may very help us to reproduce it. Further, does a restart of SketchUp help with this at first, and then later on this issue surfaces again, or is it constantly on your machine? Maybe this occurrence is generally random?
i this it is generally random, sometime restarting sketchup is a solution, sometimes not.
i think it often occur on big project on skethcup, (if the computer becomes a lil bit slowly, because of sketchup big project)
i try in small project it hasn't any problem.
and often it occur if i click on other tool for example "scale" right after put an asset library object.
and sometime it has no problem if i click asset library button on the toolbar quickly right after put an asset library object.
Thank you for the further information mm3d.arsitektur , I'll add your feedback to the corresponding bug report and we'll try to reproduce this problem ourselves again. 
I'll get back to you once I have any news regarding this subject!
Display Morei this it is generally random, sometime restarting sketchup is a solution, sometimes not.
i think it often occur on big project on skethcup, (if the computer becomes a lil bit slowly, because of sketchup big project)
i try in small project it hasn't any problem.
and often it occur if i click on other tool for example "scale" right after put an asset library object.
and sometime it has no problem if i click asset library button on the toolbar quickly right after put an asset library object.
yea im having this problem too ever since enscape added the asset library. Normally it happens like what you said, but only occur in big heavy files, 50MB and above. SO normally if this problems occur, i open another empty sketchup file and place the things i need from the asset library, then only copy to my original working file. But recently (last friday, and now) even at the empty file, the asset library window "hides" behind and can't be "call" out.
Just now i was placing a human figure into my model, then i press Esc right after i place the human figure, the windows can never comes out already.
Jackeezx , I'm very sorry to hear about that. We're still in the process of finding the cause behind this behavior but since it always seems to occur randomly, it's not possible to reproduce this faithfully right now. If anyone is able to find a way (by chance) to reproduce this issue accordingly, kindly let us know!
I am also having this problem and it is very aggrivating.
Demian Gutberlet I cannot faithfully reproduce it, because it happens every single time, I don't know if it helps but... if it never comes back until I relaunch sketchup maybe there is something to get from my log idk
**driver up to date
** never worked through all updates of enscape since its release
** wasnt working with a GTX 1060, either with GTX 1080 Ti
I often have the same experience only to find it hidden behind other windows ( not in front)
benjaminriendeau , thanks for the feedback. I'm afraid, this is (probably) something which can not be troubleshooted via log files, but you can gladly send in some feedback as described here! Thanks for the proposal.
We're still busy finding out the cause behind this - I'm afraid, this far without much success, so if anyone is able to reproduce it faithfully, kindly let us know!
