Classic and Tango style schemes: set 'text' style and others to avoid inheriting GTK default colors
There are still problems with the classic and tango style/color schemes.
I would like, for GSV 4, to set colors for all main styles in classic and tango, including the 'text' style.
These can be kept in sync with the GTK 3 colors (by manually updating the style xml files), but this would permit to avoid bad surprises.
This would permit also to avoid the problem when a dark GTK theme variant is set, while classic or tango is used (the problem being a mix of dark and light colors in the GSV widget).