Vladimir
Vladimir
@Mazzelfassel, thanks for reporting and suggesting a fix. Will try to reproduce and check your fixes.
I found a problem with margins in SaveFilePicker (but i think the same problem may be in Open/Directory pickers.. need to check) If labelWidth = 0  looks like the...
another one is we have to add Default*OpenFile/Directory/SaveFilePicker*Style  **and** set default margins ...also i recommend set Height to {DynamicResource Size.Height}; like here:  but in a Default styles as...

Suggestion, maybe it's better to set default LabelWidth value to 0... as for me it's ugly solution, because you'll never get it right:  It's better to have Label separately...
Another suggestion, but for other task -> as we working on OpenFilePicker/SaveFilePicker/Directory picker ... there is a lot of extra code here because we use MVVM approach here and controls...