Comment 8 for bug 1582930

You are right it is related to the theme.

The call of the GTK functions: gtk_widget_get_style_context, gtk_style_context_get_background_color, tk_style_context_get_color are emitting a draw signals to psensor when the widget does not have the focus.

BTW, by caching the retrieval of fg/bg colors when drawing the psensor curves, I can easily fix the CPU overuse in the Psensor code. I verified than it works, there is no more CPU overuse when the focus is lost.

I will try to commit a fix in a PPA asap.