Enhance, Transform and Effects doesn't keep parameters of options/transforms/effects. For example - change the curve, choose another option, and return to curve - there's straight, default line. But the image stays affected with options.
It is a design choise. Many raw managers take too many slides in the same panel with the risk of confusing the user.
Each GTKRawGallery tool has his own expander to permit a complete and organized overview of tools.
When you open a tool, the previously opened expander is closed, any changes are saved and slides resetted. Curves are resetted too,
so you have to undo curve and repeat the change. This permit a well organized workflow avoiding to mess with image pixels. It can be seen as a defect or an advantage. However the problem can be discussed.