Reorder DEM properties to fix vanishing color prop

Not sure why this was happening, but if you got into a state where no
VisRegion was selected, the Environment Clear Color property would also
disappear.

Reordered to put the Clear Color at the top, so that it works
consistently and also makes it more obvious that it's unrelated to the
visibility regions.

korman/ui/ui_texture.py

@@ -38,6 +38,9 @@ class PlasmaEnvMapPanel(TextureButtonsPanel, bpy.types.Panel):
         layer_props = context.texture.plasma_layer
         layout = self.layout
 
+        layout.prop(layer_props, "envmap_color")
+        layout.separator()
+
         layout.label("Visibility Sets:")
         row = layout.row()
         row.template_list("VisRegionListUI", "vis_regions", layer_props, "vis_regions", layer_props, "active_region_index",
@@ -54,9 +57,6 @@ class PlasmaEnvMapPanel(TextureButtonsPanel, bpy.types.Panel):
         if layer_props.vis_regions:
             layout.prop(rgns[layer_props.active_region_index], "control_region")
 
-        layout.separator()
-        layout.prop(layer_props, "envmap_color")
-
 
 class PlasmaLayerPanel(TextureButtonsPanel, bpy.types.Panel):
     bl_label = "Plasma Layer Options"