Merge topic 'fix_cmake_external_plugin_macro'

b817d6c Fix PARAVIEW_EXTERNAL_PLUGIN_DIRS CMake Macro
BUG #14158. Making it easier to move sliders when they overlap.

When the min and max sliders overlap, it's very hard for the users to move them.
To make that easier, added new ability to double click on the empty space on the
slider widget to move the closest slider to that position. Thus, when the two
sliders overlap, the user can double click on the left-side of the two sliders
to move the min or right-side for the max slider.

Change-Id: I24073cf403661434302ceaf2d7d0caa784f999e6
Cleanup UI for pqDoubleRangeSliderPropertyWidget.

Added label for the pqDoubleRangeSliderPropertyWidget, we were missing lable for
the threshold-range on the threshold panel, for example.

Change-Id: I53fc57709bcfd1c02198e0fd3445660f112adc66
Merge topic '14158_fix_double_range_slider' into next

1d8464f Cleanup UI for pqDoubleRangeSliderPropertyWidget.
b530d0e BUG #14158. Making it easier to move sliders when they overlap.
2ee6915 Merge topic 'fix_cmake_external_plugin_macro'