I see this issue has been raised a few times over the years but it still persists.
The leftmost (and rightmost) opacity control points in the transfer-function editor cannot be selected with the mouse because the scalar-range handle sits directly on top of them and takes priority for mouse selection, so clicking the point always grabs the range handle instead.
The only way to edit the endpoint value is via the table view. Unless you’re familiar with Paraview this behavior is not intuitive when all other points can be selected and manipulated.
Two suggestions I think would help,
- Prioritise point selection over the range handle or omit the range handle entirely from this feature or include an option to toggle the range handle feature.
- Include the option to show or toggle the table among the adjacent tool bar.
