Fix subset mixed color bug (#2579)

* Fix subset mixed color bug
* Move logic to _get_glue_value, which determines mixed state

jdaviz/configs/default/plugins/plot_options/tests/test_plot_options.py

@@ -259,8 +259,8 @@ def test_apply_presets(imviz_helper):
     arr = np.arange(36).reshape(6, 6)
     po = imviz_helper.plugins['Plot Options']
 
-    preset_colors_4 = ["#0000FF", "#00FF00", po._obj.swatches_palette[1][0],
-                       po._obj.swatches_palette[0][0]]
+    preset_colors_4 = ["#0000ff", "#00ff00", po._obj.swatches_palette[1][0].lower(),
+                       po._obj.swatches_palette[0][0].lower()]
 
     # Test applying presets with < 6 layers
 

jdaviz/core/template_mixin.py

@@ -2982,6 +2982,10 @@ def _get_glue_value(self, state):
             return getattr(state, glue_name).name
         if glue_name in GLUE_STATES_WITH_HELPERS:
             return str(getattr(state, glue_name))
+        if glue_name == 'color':
+            # Set to lower() so that all linked states of a subset
+            # (data in viewer with this subset applied) have matching color values
+            return str(getattr(state, glue_name)).lower()
         if glue_name in ('contour_visible', 'bitmap_visible'):
             # return False if the layer itself is not visible.  Setting this object
             # to True will then set both glue_name and visible to True.