Can you see which thumbnail is selected in the thumbnail bar? Neither can I. Please make the selected thumbnail clearly stand out. Reproducible: Always My KDE color scheme (it works great for all other programs): http://filebin.net/1m4i5molig/CookieDough.colors
Bump, still can't see which thumbnail is active in 4.13.1. To be clear, my choice of colors is fine, they are sufficiently contrasty. See that nice selection background showing "Cookie dough" is selected? http://i.imgur.com/E92Mldh.png The reason for the problem in this bug report is that gwenview already uses some light grey box around the thumbs, so when my "selection background" color is used which happens to be almost the same, the selected thumb the the thumb bar can't be seen.
The situation on Gwenview's Browse page is better, but not perfect: http://i.imgur.com/Dfubnfi.png
Me neither. Thankfully, the selection border is now a nice blue. Much more visible.