Scrolling in test selection menu slow

[Jonathan Cave]

Version:

$ ls parts/plainbox-provider-plano/ubuntu/download/ | grep checkbox
checkbox-ng_0.22+bzr4086+pkg33~ubuntu15.10.1_all.deb
python3-checkbox-ng_0.22+bzr4086+pkg33~ubuntu15.10.1_all.deb
python3-checkbox-support_0.22+bzr4086+pkg24~ubuntu15.10.1_all.deb

Steps to reproduce:
 - Run a test suite using the checkbox-ng front end from the above packages
 - Enter in to the menu that allows you to select the tests to run (there should be a reasonable number of tests in the lists e.g ~40
 - Use the up/down arrow keys to scroll through the list

Expected result:
 - the selected line moves up and down the list smoothly and the interface remains responsive

Actual result:
 - the interface quickly slows down and becomes quite unresponsive
 - running top on another console shows the python process consuming a lot (all) of the CPU

[Zygmunt Krynicki (zyga)]

I strongly suspect this is just uber-naive code in textland. I'll try to reproduce this with a scrolling demo that is capped at 60fps to see what's the slow part.

[Sylvain Pineau (sylvain-pineau)]

We did improve the lag in the textland menus, it can still be improved but it's less critical now.