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bl_info = {
    "name": "tester",
    "description": "",
    "author": "",
    "version": (0, 0, 3),
    "blender": (2, 70, 0),
    "location": "3D View > Toolbox",
    "warning": "", # used for warning icon and text in addons panel
    "wiki_url": "",
    "tracker_url": "",
    "category": "Test"
}

import bpy
import re
import math
from mathutils import Vector
from math import pi

from bpy.props import (StringProperty,
                       BoolProperty,
                       IntProperty,
                       FloatProperty,
                       FloatVectorProperty,
                       EnumProperty,
                       PointerProperty,
                       )
from bpy.types import (Panel,
                       Operator,
                       AddonPreferences,
                       PropertyGroup,
                       )


# ------------------------------------------------------------------------------------------------
# get object type list
# ------------------------------------------------------------------------------------------------

def get_groupItems():
    items = None
    def func(self, context):
        items = [(group.name, group.name, "") for group in bpy.data.groups]
        return items
    return func

# ------------------------------------------------------------------------
#    store properties in the active scene
# ------------------------------------------------------------------------

class MySettings(PropertyGroup):
    
    search_selection = StringProperty(name="Group")

    enum_selection = EnumProperty(
        name="Apply Data to:",
        description="Apply Data to attribute.",
        items=get_groupItems()
        )

# ------------------------------------------------------------------------
#    myTool in objectmode
# ------------------------------------------------------------------------

class OBJECT_PT_my_panel(Panel):
    bl_idname = "OBJECT_PT_my_panel"
    bl_label = "My Panel"
    bl_space_type = "VIEW_3D"
    bl_region_type = "TOOLS"
    bl_category = "TESTER"
    bl_context = "objectmode"

    def draw(self, context):
        layout = self.layout
        scene = context.scene
        mytool = scene.my_tool
        
        layout.prop_search(mytool, "search_selection", bpy.data, "groups")
        layout.prop(mytool, "enum_selection", text="")
        print (mytool.search_selection)
        print (mytool.enum_selection)


# ------------------------------------------------------------------------
# register and unregister functions
# ------------------------------------------------------------------------

def register():
    bpy.utils.register_module(__name__)
    bpy.types.Scene.my_tool = PointerProperty(type=MySettings)

def unregister():
    bpy.utils.unregister_module(__name__)
    del bpy.types.Scene.my_tool

if __name__ == "__main__":
    register()