add invisible material hide in check layers func

OP_setup_layers.py

@@ -184,10 +184,16 @@ class GPEXP_OT_layers_state(bpy.types.Operator):
         default=True, description='Check/Set blend mode to regular') # , options={'SKIP_SAVE'}
 
     clear_frame_out_of_range : BoolProperty(name='Clear Frames Out Of Scene Range',
-        default=False, description='Delete frames that before scene start and after scene end range\nWith a tolerance of one frame to avoid problem\nAffect all layers)') # , options={'SKIP_SAVE'}
+        default=False, description='Delete frames that before scene start and after scene end range\
+            \nWith a tolerance of one frame to avoid problem\
+            \nAffect all layers)') # , options={'SKIP_SAVE'}
 
     opacity_exclude_list : StringProperty(name='Skip',
-        default='MA', description='Skip prefixes from this list when changing opacity\nSeparate multiple value with a comma (ex: MA,IN)') # , options={'SKIP_SAVE'}
+        default='MA', description='Skip prefixes from this list when changing opacity\
+            \nSeparate multiple value with a comma (ex: MAIN)') # , options={'SKIP_SAVE'}
+
+    hide_invisible_materials : BoolProperty(name='Hide Materials named invisible',
+        default=True, description='Hide material with name starting with "invisible"') # , options={'SKIP_SAVE'}
 
 
     @classmethod
@@ -222,6 +228,7 @@ class GPEXP_OT_layers_state(bpy.types.Operator):
             row.prop(self, 'opacity_exclude_list')
         layout.prop(self, 'set_use_lights')
         layout.prop(self, 'set_blend_mode')
+        layout.prop(self, 'hide_invisible_materials')
         # layout.prop(self, 'clear_unused_view_layers')
 
     def execute(self, context):
@@ -312,6 +319,14 @@ class GPEXP_OT_layers_state(bpy.types.Operator):
         if gp_mu_edit_ct:
             changes.append(f'{gp_mu_edit_ct} multiframe-edit mode disabled')
 
+        ## Hide invisible named materials
+        if self.hide_invisible_materials:
+            for m in bpy.data.materials:
+                if m.is_grease_pencil and m.name.lower().startswith('invisible'):
+                    if not m.grease_pencil.hide:
+                        print(f'Hiding gp material {m.name}')
+                        m.grease_pencil.hide = True
+                        changes.append(f'{m.name} material hidden')
 
         fn.show_message_box(_message=changes, _title="Layers Check Report", _icon='INFO')