Good news, I updated this morning to 54.0.2840.87 (64-bit) and the search seams to work again!
It's still sometimes extremely slow, hangs or returns only the filenames without results under them (wasn't the case before).
But this report can probably be closed, i will reopen it when it occurs again.

ps. I'm running Chrome with
open  -a  /Applications/Google\ Chrome.app -F -n --args --allow-running-insecure-content --disable-web-security --user-data-dir 

ps2. If i find more time i will try to find the version that caused the slowdown of the search and test it without insecure mode but it shouldn't affect developer tools

Thank you Teo for the bugreport. Closing for now then

Sorry it's still an open issue. I just recorded a video. At the end devtools disappears and the whole website dies.

See it in the video. A the beginning I'm pressing Enter multiple times to perform the search, at the end the tab dies and nothing is clickable. I checked the task manager, the CPU is fine so it's not a issue with it.
https://www.youtube.com/watch?v=JQKMPaSQDrc


Chrome Version 54.0.2840.87 (64-bit)

Hard to reconstruct,could be also because of the 
open  -a  /Applications/Google\ Chrome.app -F -n --args --allow-running-insecure-content --disable-web-security --user-data-dir 

mode I'm using but would not make much sense that it affects it. After killing the tab and reopening it everything works again but not for long.
The same thing is also with search.. Sometimes it just hangs, the CPU is fine but it just needs a lot of time to display the search results this happens often. Closing the tab and reopening it usually fixes the search hanging issue. Just closing the devtools doesn't work i think or it causes the issue seen in the video that it gets white

Teo, thank you for the report. Does this help for you on Chrome Canary as well?

I didn't had time to test it in that configuration. Now i closed webstorm(CSS cut bug) and switched to chrome canary.
I will test it for the next two weeks, if it doens't happen again in the next two weeks consider it fixed.

Sorry It's still there on Canary:
https://www.youtube.com/watch?v=P5g9QInepLI

Version 56.0.2920.0 canary (64-bit)

The warning counter gets crazy pls take a look at it. Also it didn't wanted to load the evetServise.js file it said it was an empty file then after a while it loaded the file(probably another bug)

Maybe a workspace binding issue.

I can debug developer tools if needed. Can i use the plugin write procedure to debug it ? , If so could you give me some hints where to search if it happens again or i can give you a remote session to my system when it happens again.

Could be that the warnings are:
[Violation] Long running JavaScript task took X ms

but i am not sure

The "Violation" messages have no relation to this issue - these are about inspected page.

Youtubes are helpful, thanks. I managed to occasionally repro the bug.

What is a "plugin write" procedure? If you just open devtools on devtools next time and report all the warning in the console, that would help.

Same issue here...
Windows 7
Chrome Version 54.0.2840.99 (64-bit)

Its slow but sometimes it gets stuck. Got this error trough inspecting devtools
http://image.prntscr.com/image/fc152739693945498a240bfa5cd60a10.png

Teo, do you have a reliable repro? It would help me a lot!

Seems to be better in: Version 55.0.2883.75 (64-bit) lets hope it stays like that it happens from time to time. 
Will ask my colleague if it's still an issue 

Ok, so we managed to reproduce this.
Step-by-step:
1. Open devtools on devtools
2. Put breakpoint on the first line of Runtime.js
3. Reload first devtools to hit breakpoint
4. Try to search across all files.

Actual: the search gets stuck.

The reason: InspectorPageAgent::searchInResource method tries to load missing content via the resourceloader, which, apparently, doesn't work in paused state.

Our options:
1. Try to preload content when devtools gets opened
2. Learn how to load resource contents in paused state