When the browser’s width is resized to a small width and then back to the orignal size, the background of some elements does not change.
Its’ a little difficult to explain, so here is a GIF:
Tried the same on even this support forum, resize the browser width to about say 150px and then back to say 1000px, some borders go black…
Its the same with the samples that came with webix. Tried other sites and its not the issue there, clearly an issue with webix.
Browser: Firefox Version 39 BuildID 20150630154324