Some customers have reported issues with Spread.NET 12 Windows Forms and VB.NET design time. These issues, and a few others reported by customers, are now fixed in the latest version 12.45.20181.2 that was posted February 13, 2019.
To get this updated version of Spread.NET 12 Windows Forms, you must uninstall and reinstall the Windows Forms controls. To uninstall the Windows Forms controls, use Control Panel – Programs and Features and remove “Spread for WinForms 12” completely.
The issues fixed in this update are:
268328, 268407 Errors loading the form containing Spread.NET 12 Windows Forms in VB.NET.
269287 Cell comments not loading correctly importing XLSM with DocumentCacheing.
269470 Exception thrown from SheetViewCollection.RemoveAt after importing certain Excel documents.