Is it possible to make icons smaller?
Tray Icons
What applications are those with color blue?
No, it isn't possible.
That's not good, it looks awful ><
I also have this issue with Google Play Music Desktop Player. The tray icon is huge compared to the others. 
Especially once you have a lot of icons from different apps in the tray, it starts to look really funky.
I had this with open-drive and hexchat, but fixed them.
- Edited
Yes. Hack is a big word. Added telegram also:
- Edited
- Hexchat is easy, just copy the .png icons to
$HOME/.config/hexchat/icons. I made some icons using inkscape and I uploaded them in github. - Same with telegram. The icons should be placed to
$HOME/.local/share/TelegramDesktop/tdata/ticons. You can find on github a lot icons for telegram. For telegram I have found a script to generate icons as much as you want. This is the script. - About odrive. I have packaged it localy using my icons for tray.