Fix WPF databinding with UpdateSourceTrigger="LostFocus"
In WPF e.g. for a TextBox databindings are usually using UpdateSourceTrigger="LostFocus".
This is however broken in various ways. For example put the textbox in a TabControl, edit the text and switch tab. The data is lost.
There are various "workarounds" but they all have their own problems. This is a well known bug and it should be fixed.
(Or at least an alternative UpdateSourceTrigger="LostFocusFixed" mode should be added that actually works all the time.)