Excel, switching between worksheets is "jumpy"

[BarneyRub]

Hi

I have a large and complex Excel workbook. The 1st worksheet acts as a hub for various tasks which are called through various buttons. I don't want it to look Excel'ish so I have disabled the following:
Excel ribbon
scrollbars
tabs
formula bar

The 2nd worksheet also has the same features disabled.

There is a 3rd worksheet which needs to have the above features enabled. To select the 3rd worksheet a button is clicked on either of the 1st 2 worksheets.

The activation of the 3rd worksheet is not smooth - it is very jumpy, redrawing the screen and enabling the ribbon, scroll bars, tabs and formula bar. I have used Application.ScreenUpdating but it doesn't help.

Any suggestions to improve this would be most welcome!
N.B. The 1st 2 worksheets would have most use with much lower use for the 3rd worksheet.

Thanks
Bill