Make it simpler to change the scale in the 3D view
It takes more effort that is necessary to rescale the colour bar, i.e.
* click the colour scale editor
* untick automatically rescale
* click rescale range
* update range in new dialog window
* click rescale
* close dialog
* Remove the unnecessary extra dialog for the range (include in the main dialog window)
* Colour editor dialog could be available as a context menu from the 3D view
* Middle click and drag could select the range from the 3D view
The Color Map Editor available since ParaView 4.1 addresses several of these issues.