Unintuitive behavior of RangeEditor when mode is explicitly set

Currently the actual range editor used in a "View" do not always conform to the one specified with the mode option, which is unintuitive.
For example if the range is given by low=0 and high=None the actual range editor used is always RangeTextEditor no matter if you specified mode='xslider' or mode='spinner'. That is unexpected. I would expect that explicit set mode would take precedence over automatic settings.

The lines controlling this behavior is given below in _get_simple_editor_class and _get_custom_editor_class methods:

https://github.com/enthought/traitsui/blob/87dceb219b8b7b547907f031aaca70e1a66b7945/traitsui/editors/range_editor.py#L214-L245

https://github.com/enthought/traitsui/blob/87dceb219b8b7b547907f031aaca70e1a66b7945/traitsui/editors/range_editor.py#L247-L271