Bad Combobox behaviour with new items

[JulienKluge]

A comboboc, with assigned metro style, behaves bad with new items in the actual drop-down-size.
At exmaple:

1. make a combobox with 2 items.
2. open the drop down menu
3. close the drop down
4. clear all items
5. add 4 new items
   You'll see that the dropdown, still has the size of 2 items which hides the other 2.
   Also no scrollbar is visible to get to the other 2.

[laynor]

Having the same problem here. The combobox dropdown is not resizing properly, it tends to keep the initial size. This doesn't happen all the time to me, but I would say most of the time.
This applies also when deleting an item: an empty, unselectable space will be show in the dropdown.

[punker76]

@TheJelle @laynor can't repro this issue... any other special cases?

[JulienKluge]

My program https://github.com/TheJelle/OpenDeCoder suffers from this bug.
Download it and look into OpenDeCoder/UI/Components/ParameterControl.xaml.
There is one line:

<ComboBox ... Style={x:Null} ... />

Remove the style attribute, rebuild the solution, and you'll be able to reproduce the bug.
(Start; Select 'From ASCII'-Listmenuitem; Open the Combobox above;
Select 'DeCoding'-TabItem; Select 'Morse'-Listmenuitem; Open Combox above;
BUFF bug! - do it reverse to see it the other way around)