better cam ref UI and clear keyframe ops

1.0.4:

- UI: Better cam ref exposition in Toolbox panel
  - Access to opacity
  - merge activation bool with source type icon
- feat: Added a clear active frame operator (`gp.clear_active_frame` to add manually in keymaps)

__init__.py

@@ -15,7 +15,7 @@ bl_info = {
 "name": "GP toolbox",
 "description": "Set of tools for Grease Pencil in animation production",
 "author": "Samuel Bernou",
-"version": (1, 0, 3),
+"version": (1, 0, 4),
 "blender": (2, 91, 0),
 "location": "sidebar (N menu) > Gpencil > Toolbox / Gpencil properties",
 "warning": "",
@@ -371,7 +371,7 @@ class GPTB_prefs(bpy.types.AddonPreferences):
         if self.pref_tabs == 'MAN_OPS':
             # layout.separator()## notes 
             # layout.label(text='Notes:')
-            layout.label(text='Following operators ID have to be set manually :')
+            layout.label(text='Following operators ID have to be set manually in keymap if needed :')
             
             ## keyframe jump
             box = layout.box()
@@ -391,6 +391,13 @@ class GPTB_prefs(bpy.types.AddonPreferences):
             row.label(text='Replace wanted by "view3d.cusor_snap"')
             row.operator('wm.copytext', text='Copy "view3d.cusor_snap"', icon='COPYDOWN').text = 'view3d.cusor_snap'
             box.label(text='Or just create a new shortcut using cursor_snap')
+            
+            ## Clear keyframe
+            box = layout.box()
+            box.label(text='Clear active frame (delete all strokes without deleting the frame)')
+            row = box.row()
+            row.label(text='gp.clear_active_frame')
+            row.operator('wm.copytext', icon='COPYDOWN').text = 'gp.clear_active_frame'
 
             ## user prefs 
             box = layout.box()