When I hit g (to debug) and I close a view to get to main view,
I get these messages in WinDbg:
System.Windows.Data Error: BindingExpression path error: 'TileTitle' property not found on '' 'System.String' (HashCode=757602046). BindingExpression: Path='TileTitle' DataItem='' (HashCode=757602046); target element is 'System.Windows.Controls.TextBlock' (Name=''); target property is 'Text' (type 'System.String')..
System.Windows.Data Error: BindingExpression path error: 'TileTapCommand' property not found on '' 'System.String' (HashCode=757602046). BindingExpression: Path='TileTapCommand' DataItem='' (HashCode=757602046); target element is 'System.Windows.Controls.Button' (Name=''); target property is 'Command' (type 'System.Windows.Input.ICommand')..
How can I solve these? Are these really a problem? Does it cause a memory leak?
The messages you see are not exceptions, they are debug output. You should see the same using DebugView (SysInternals), it is not WinDbg specific.
In case of an unhandled exception, WinDbg would stop and you could analyze it. In case of a first chance exception that got caught, no output would be generated (unless implemented by the developer).
As pointed out by Patrick already, see WPF Error 40 BindingExpression path error on how to read the output and find the place to fix it.
If you can't notice any failure while using the program, you might not need the binding at all and you can just remove it. However, someone put it there, surely for some reason - find out who it was (the answer is given by your version control system) and ask him why he implemented the binding. Maybe you find an undocumented requirement and then you see the failure that is caused by the missing binding.
Since the missing binding is something that is not there, this does not cause a memory leak.