ui.py

import bpy
from .color_by_axis_edges import CBA_Edges


class CBA_PT_Main_Panel(bpy.types.Panel):
    bl_idname = "CBA_PT_Main_Panel"
    bl_label = "Color by Axis"
    bl_space_type = "VIEW_3D"
    bl_region_type = "UI"
    bl_category = "Color by Axis"

    def draw(self, context):

        @classmethod
        def poll(self, context):
            if context.mode != "OBJECT":
                return True
            else:
                return False

        layout = self.layout
        layout.operator_context = "INVOKE_DEFAULT"

        scene = context.scene
        col1 = layout.column()
        col1.label(text="Axis Type:")
        col1.prop(scene, "axis_type", text="")
        col2 = layout.column()
        col2.label(text="Reference Object")
        col2.prop_search(scene, "axis_ref", scene, "objects", text="")
        layout.prop(scene, "draw_permanent")
        layout.prop(scene, "draw_in_front")
        layout.prop(scene, "line_width")