Theming issues noted while porting Weather applet

[Friedrich W. H. Kossebau]

Hi,

happy to have the weather applet almost revived and good enough to have your 
eyes on it (hopefully in time for 5.6), see parallel emails for https://
git.reviewboard.kde.org/r/127193/

Some issues I noticed which seem unrelated to the weather applet code, are 
these known or should be filed as bugs? (Seen with Plasma 5.5.4) 

* PlasmaCore.FrameSvgItem seems to not update to changes of the Plasma color 
theme, stays with theme current on start
* QtControls.ComboBox drop-down menu background seems to ignore Plasma color 
theme (results in white on white text with dark Breeze theme)

Or are these due to usage errors still? If so, what to do?

Cheers
Friedrich