kivy gridlayout problem

gloproblem.py

from kivy.uix.gridlayout import GridLayout
from kivy.uix.label import Label
from kivy.uix.image import Image

from kivy.app import Builder, App
from random import randint

Builder.load_string("""

<GridLayout>:
    canvas:
        Color:
            rgba: 1,0,0,1
        Line:
            rectangle: self.x+1,self.y+1,self.width-1,self.height-1

<Image>:
    canvas:
        Color:
            rgba: (0,1,0,0.3)
        Rectangle:
            pos: self.pos
            size: self.size
            
<Label>:
    text_size: self.width, None
    size_hint_y: None
    height: self.texture_size[1]
    
""")


class ACListEntry(GridLayout):
    def __init__(self, **kwargs):
        super(ACListEntry, self).__init__(cols=2, size_hint_y=None, **kwargs)
        self.bind(minimum_height = self.setter("height"))

        img = Image(size_hint = (None,None), size = (60,60), source = "")
        self.add_widget(img)

        lbl = Label(text="TEST layout problem fds af dfsad fsd asdfs adfsad fdsf "*randint(1,6))
        self.add_widget(lbl)
        
        
class MyApp(App):
    def build(self):

        mainlayout = GridLayout(cols=1)
        
        for _ in xrange(5):
            mainlayout.add_widget(ACListEntry())
        
        return mainlayout


MyApp().run()

Hey guys, any ideas why the code above doesn't produce the expected result? ACListEntry ends up very tall. definitely not the minimum_height.

workaround:
https://gist.github.com/Alan-FGR/c8e14994e7465398d5ed