Steps to reproduce:
Press "Choose tryjobs" below the list of the changed fils.

Expected result:
The popup with list of available tryjobs to choose from.

Actual result:
After pressing Choose tryjobs button at https://webrtc-review.googlesource.com the screen blacks as if there's a pop up on the page, but the popup itself never appears. If I press the escape key, the invisible popup closes.

I use Chrome 66.0.3359.181 with my @webrtc.com account logged it.