When tabs are not shown, and the notebook is used as a container,
we should not set the notebook style, otherwise the theme has no
way to know whether tabs are shown or not, and which colour to draw
the background.
https://bugzilla.gnome.org/show_bug.cgi?id=640692
Writing onto the passed-in GtkStateData could cause changes that would
propagate to siblings, as the data was not reset again.
By copying the data structure, this is avoided and the proper values are
passed to sibling widgets.
Commit 4bb3d64414 introduced a limitation
to GtkRange style properties; when stepper-spacing is > 0,
trough-under-steppers is automatically set to FALSE; this means that
setting a spacing between the steppers (e.g. the scrollbar buttons) and
the trough (i.e. the area over which the slider is free to move) would
make the buttons always get the full allocation on the !orientation
direction.
The rationale is without this limitation, you would get an area which
seems clickable, but it's actually not.
While this is true, and undesirable, for big stepper spacings, themes
that use trough-under-steppers (which is TRUE by default anyway),
might want to set smaller spacings to avoid drawing a double line between
the button and the slider borders.
To add confusion, the documentation got it flipped, i.e. it stated
setting a positive stepper-spacing would set trough-under-steppers to
TRUE (which would also make the behavior expected by commit
4bb3d64414 impossible).
I don't think hardcoding either of the two limitations is a good thing.
We should let themes handle this instead, and remove this limitation. If
you want the old behavior, you can manually set trough-under-steppers to
FALSE if you set a positive stepper-spacing in your theme.
https://bugzilla.gnome.org/show_bug.cgi?id=644777
Ensure that we're writing all the updates for a single rendering op
in one go without callbacks inbetween. That way some rendering will
be delayed, but the user will never see partial renderings.
