I had to remove the `isVisible` check in `MyExpander::set_expanded()`
because it would trigger in Wavelet and Retinex for unknown reasons.
One inner expander in CIECAM isn't covered by the tool states, and the
way they are distributed to Wavelet and Retinex won't allow for further
tool states in those tools. We should consider to move the tool states
for sub-tools (like Wavelet, Retinex, and CIECAM) to seperate keys in
the `options` file.
This commit include :
- cleanup rtgui/retinex.cc file (constructor only) and switched to
Gtk::Grid (the new standard) instead of Gtk::Box. This however doesn't
solve the issue of the Transmission curves in the Retinex tool, with
wrong resize of the Frame when folding/unfolding the curves.
- better alignment of the Histogram panel now with 4px of padding on the
left and right side
- Threshold selector now use the Scale's Trough style to draw its box
and sliders
- Curve's background are darker and restricted to the curve diagram
- Diagonal and Flat curves has been converted to Gtk::Grid as well
- A special color is now used for unsensitive Threshold selector and
Sclaes widgets
- Gap around the main Window has been removed on windows to circumvent a
bug in Gtk3, but the window can now only be maximized (usual use case)
or resized vertically by the top border only.
- Buttons at the bottom of the Editor panel has now the same height
