Password box - has top and and left darker border

[MichaelHughes]

The zip file contains a Password box which alternates with a TextBox depending on the checked nature of a CheckBox - they both have the same DataContext so have the same text values.

They are the same size (I thought) and I switch between them with a password on/off option. The Password box does not seem to have this option. This worked fine in version 1.2.4 (except the text and stars do jump a little due to misalignment - I can probably improve this with padding BUT the major issue is the two really black lines when I swith to Password - the left and the top show thick black borders while the bottom and right seem normal.

Any ideas why - any better ways to create a password box that allows the text to be shown as well.

Thanks