Create ui module

This is where you put all your panels, menus, ui lists, etc.
For panels I usually put everything in a column, because I prefer how the spacing looks.

Author: bonjorno7

addon/ui/__init__.py

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+import bpy
+from . import example_panel
+
+
+classes = (
+    example_panel.ExamplePanel,
+)
+
+
+def register():
+    for cls in classes:
+        bpy.utils.register_class(cls)
+
+
+def unregister():
+    for cls in reversed(classes):
+        bpy.utils.unregister_class(cls)

addon/ui/example_panel.py

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+import bpy
+from .. import utils
+
+
+class ExamplePanel(bpy.types.Panel):
+    bl_idname = 'EXAMPLE_PT_ExamplePanel'
+    bl_category = 'Example'
+    bl_label = 'Example Panel'
+    bl_space_type = 'VIEW_3D'
+    bl_region_type = 'UI'
+
+
+    def draw(self, context):
+        column = self.layout.column()
+
+        box = column.box()
+        utils.ui.draw_op(box, 'Useless Button', 'example.example_operator')