Property Value is white if it isn't ReadOnly

So hi guys,

I'm having a small problem here... If my property value in my propertyGrid isn't set to ReadOnly, the appears white. I tested this by copying the white string(in this case) into word, and it appeared as i set it. So when the value is white, i simply can't read it.

Screenshot:

So property 1,2,4,5 are all 'not readonly. While Property 3 and 6 are readonly. Why does this happen, how can i prevent it?

Edit:

Code:

<propgrid:PropertyGrid x:Name="propGrid" Grid.Column="0" MinHeight="300" Width="300" HorizontalAlignment="Left">
<propgrid:PropertyGrid.Properties>
<propgrid:PropertyGridPropertyItem ValueName="Property1" Value="Value1" DefaultValue="DefaultValue1"
Description="This is the first property." Category="Category1" />
<propgrid:PropertyGridPropertyItem ValueName="Property2" Value="Value5" DefaultValue="DefaultValue2"
Description="This is the second property." Category="Category1" IsModified="True" />
<propgrid:PropertyGridPropertyItem ValueName="Property3" Value="Value5" DefaultValue="Value3"
Description="This is the third property." IsReadOnly="True" Category="Category1" />
<propgrid:PropertyGridPropertyItem ValueName="Property4" Value="Value1" DefaultValue="DefaultValue1"
Description="This is the first property." Category="Category2" />
<propgrid:PropertyGridPropertyItem ValueName="Property5" Value="Value2" DefaultValue="DefaultValue2"
Description="This is the second property." Category="Category2" />
<propgrid:PropertyGridPropertyItem ValueName="Property6" Value="Value3" DefaultValue="Value3"
Description="This is the third property." IsReadOnly="True" Category="Category2" />
</propgrid:PropertyGrid.Properties>
</propgrid:PropertyGrid>

Thank You