Incomplete transparency in panel and mouse hover issues with custom command plugin

[stefonarch]

I noticed a small amount of issues:

• If there is opacity set clock, volume and menu have none in silver, arch-colors and valendas theme
• Custom command plugin text goes invisibile or "jumps" on mouseover in (at least) ambiance and arch-colors.

Maybe there are more themes/plugins affected.

Context

Under labwc panel doesn't hide on fullscreen videos and transparency is nice therefor.

System Information

• Distribution & Version: latest git

[stefonarch]

Mostly fixed, there are still issues in silver with quicklaunch buttons and in "system" theme with brightness: