This morning I updated Windows 10 with a cumulative update for Windows 10 Version 1703 for x64-based systems (KB4032188) which seems to have fixed the delay in both Paratext 7 and 8. The Knowledge Base article has this statement: “Addressed issue where some Windows Forms (WinForms) applications that use DataGridView, Menu controls, or call a constructor for a Screen object experienced performance regressions in .NET 4.7. This was caused by additional Garbage Collections. In some cases, there was an empty UI because of a lack of GDI+ handles.”