The file dialog is always grouping numbered file together (file series) but it should not

FileSeries grouping is used when showing multiple file numbered like this

foo_0.vtk
foo_1.vtk
foo_2.vtk

However, this grouping make sense only if the user is doing File -> Open. It also do not make sense with folders.

Any other case should not group file together, this includes but is not limited to :

Save Data, Load State, Save State, CustomFilters import/export, Camera path import/export, preset import/export...

https://discourse.paraview.org/t/mis-display-the-filename-while-load-state-file-in-paraview5-8-0-windows-10/3750