diff --git a/CHANGELOG.md b/CHANGELOG.md
index 69bb510..8696b71 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,10 @@
 # Changelog
 
+
+1.5.6
+
+- feat: layer drop-down menu include an operator for batch find/replace GP layers (idname: `gp.rename_gp_layers`)
+
 1.5.5
 
 - feat: check file: add check for filepath mapping (if all relative or all absolute)
diff --git a/OP_layer_manager.py b/OP_layer_manager.py
index 69b8cc1..d36faa2 100644
--- a/OP_layer_manager.py
+++ b/OP_layer_manager.py
@@ -187,42 +187,49 @@ class GPTB_OT_select_set_same_color(Operator):
         return {"FINISHED"}
 
 
-def replace_layer_name(target, replacement, selected_only=True, prefix_only=True):
+def replace_layer_name(target, replacement, selected_only=True, prefix_only=True, regex=False):
     prefs = get_addon_prefs()
     sep = prefs.separator
     if not target:
         return
-    scene = bpy.context.scene
+
     gpl = bpy.context.object.data.layers
 
-    if scene.gp_rename_selected:
-        lays = [l for l in gpl if l.info != 'background' and l.select]
+    if selected_only:
+        lays = [l for l in gpl if l.select] # exclude : l.info != 'background' 
     else:
-        lays = [l for l in gpl if l.info != 'background']
+        lays = [l for l in gpl] # exclude : if l.info != 'background'
 
     ct = 0
     for l in lays:
-        if scene.gp_rename_prefix:
-            old = l.info
+        old = l.info
+        if regex:
+            new = re.sub(target, replacement, l.info)
+            if old != new:
+                l.info = new
+                print('rename:', old, '-->', new)
+                ct += 1
+            continue
+
+        if prefix_only:
+            if not sep in l.info:
+                # only if separator exists
+                continue
             splited = l.info.split(sep)
             prefix = splited[0]
-            #print(1, splited)
             new_prefix = prefix.replace(target, replacement)
-            #print(2, splited)
             if prefix != new_prefix:
                 splited[0] = new_prefix
-                #print(3, splited)
                 l.info = sep.join(splited)
                 print('rename:', old, '-->', l.info)
-                ct+= 1
+                ct += 1
 
         else:
-            old = l.info
             new = l.info.replace(target, replacement)
             if old != new:
-                print('rename:', old, '-->', l.info)
                 l.info = new
-                ct+= 1
+                print('rename:', old, '-->', new)
+                ct += 1
     return ct
 
 class GPTB_OT_rename_gp_layer(Operator):
@@ -237,11 +244,12 @@ class GPTB_OT_rename_gp_layer(Operator):
 
     find: StringProperty(name="Find", description="Name to replace", default="", maxlen=0, options={'ANIMATABLE'}, subtype='NONE')
     replace: StringProperty(name="Repl", description="New name placed", default="", maxlen=0, options={'ANIMATABLE'}, subtype='NONE')
-    selected: BoolProperty(name="Selected layer only", description="Affect only selected layers", default=True)
-    prefix: BoolProperty(name="Prefix only", description="Affect only prefix of name (full name if not '_' in it)", default=True)
+    selected: BoolProperty(name="Selected Only", description="Affect only selected layers", default=False)
+    prefix: BoolProperty(name="Prefix Only", description="Affect only prefix of name (skip layer without separator in name)", default=False)
+    use_regex: BoolProperty(name="Regex", description="use regular expression (advanced), equivalent to python re.sub()", default=False)
 
     def execute(self, context):
-        count = replace_layer_name(self.find, self.replace, selected_only=self.select, prefix_only=self.prefix)
+        count = replace_layer_name(self.find, self.replace, selected_only=self.selected, prefix_only=self.prefix, regex=self.use_regex)
         if count:
             mess = str(count) + ' layers renamed'
             self.report({'INFO'}, mess)
@@ -255,12 +263,19 @@ class GPTB_OT_rename_gp_layer(Operator):
 
     def draw(self, context):
         layout = self.layout
-        #layout.separator()
-        #layout.label('search/replace GPlayers')
-        layout.prop(self, "selected")
-        layout.prop(self, "prefix")
-        layout.prop(self, "find")#, text = 'find')
-        layout.prop(self, "replace")#, text = 'replace')
+        row = layout.row()
+        row_a= row.row()
+        row_a.prop(self, "selected")
+        
+        row_b= row.row()
+        row_b.prop(self, "prefix")
+        row_c= row.row()
+        
+        row_c.prop(self, "use_regex")
+        row_b.active = not self.use_regex
+
+        layout.prop(self, "find")
+        layout.prop(self, "replace")
 
 
 ## --- UI layer panel---
@@ -313,6 +328,12 @@ def gpencil_dopesheet_header(self, context):
     row.operator('gp.select_same_color', text='', icon='RESTRICT_COLOR_ON')
 
 
+## --- UI context menu ---
+
+def gpencil_layer_dropdown_menu(self, context):
+    '''to append in GPENCIL_MT_layer_context_menu'''
+    self.layout.operator('gp.rename_gp_layers', icon='BORDERMOVE')
+
 classes=(
     GPTB_OT_rename_gp_layer,
     GPTB_OT_layer_name_build,
@@ -326,8 +347,10 @@ def register():
     
     bpy.types.DATA_PT_gpencil_layers.prepend(layer_name_builder)
     bpy.types.DOPESHEET_HT_header.append(gpencil_dopesheet_header)
+    bpy.types.GPENCIL_MT_layer_context_menu.append(gpencil_layer_dropdown_menu)
 
 def unregister():
+    bpy.types.GPENCIL_MT_layer_context_menu.remove(gpencil_layer_dropdown_menu)
     bpy.types.DOPESHEET_HT_header.remove(gpencil_dopesheet_header)
     bpy.types.DATA_PT_gpencil_layers.remove(layer_name_builder)
     
diff --git a/__init__.py b/__init__.py
index 532d6b7..1394bc1 100755
--- a/__init__.py
+++ b/__init__.py
@@ -15,7 +15,7 @@ bl_info = {
 "name": "GP toolbox",
 "description": "Set of tools for Grease Pencil in animation production",
 "author": "Samuel Bernou, Christophe Seux",
-"version": (1, 5, 5),
+"version": (1, 5, 6),
 "blender": (2, 91, 0),
 "location": "Sidebar (N menu) > Gpencil > Toolbox / Gpencil properties",
 "warning": "",