Be careful not to unload current project if settings imported from it.

Fixes https://gitlab.com/kicad/code/kicad/issues/5684

pcbnew/dialogs/dialog_board_setup.cpp

@@ -185,6 +185,7 @@ void DIALOG_BOARD_SETUP::OnAuxiliaryAction( wxCommandEvent& event )
             DisplayErrorMessage( this, msg, ioe.What() );
         }
 
+        if( otherPrj != &m_frame->Prj() )
             m_frame->GetSettingsManager()->UnloadProject( otherPrj, false );
 
         return;
@@ -228,10 +229,12 @@ void DIALOG_BOARD_SETUP::OnAuxiliaryAction( wxCommandEvent& event )
         if( importDlg.m_SeveritiesOpt->GetValue() )
             m_severities->ImportSettingsFrom( otherBoard->GetDesignSettings().m_DRCSeverities );
 
+        if( otherPrj != &m_frame->Prj() )
             otherBoard->ClearProject();
     }
 
     // Clean up and free memory before leaving
+    if( otherPrj != &m_frame->Prj() )
         m_frame->GetSettingsManager()->UnloadProject( otherPrj, false );
 
     delete otherBoard;