Sheet Protection "select unlocked cells" doesn't repond the same between sheets

XL '02

In my workbook I have multiple sheets with generally 90% of the cells locked & hidden under sheet protection invoking "Select unlocked cells" [the only permission checked] . Most sheets allow cell highlight with selection, that's perfect.
But, my primary sheet will allow cell selection [of unlocked cells] but will not highlight the cells. This sheet does have about 25 dropdowns from Control Toolbox with their underlying cells unlocked for proper function. The sheets providing cell highlights do not have any dropdowns. This is the only difference I can see between all the sheets.

Anyone have a clue to why this is happening?

I've partially resolved this myself with placing this code in the Workbook_Open Object Code File:

It remedied the user permission to highlight the selected unlocked cells and to reinstate same permissions upon Save - Close - ReOpen, BUT, I've lost keyboard cell selection functions on the main sheet only. I must have a conflict on this main sheet somewhere. Time to dig into it.

If anyone has any known or assumed conditions that can cause this I would appreciate any suggestions.

For Each sh In ActiveWorkbook.Worksheets
     sh.EnableSelection = xlUnlockedCells
     sh.Protect     'sans pword
Next sh

My Workbook has 17 worksheets. Cell selection via mouse & keyboard function as they should for all but 1 sheet, my primary sheet. The primary sheet while protected & permitting "Select unlocked cells" will only allow cell selection via mouse it will not allow keyboard selections! It's a non issue with the other 16 sheets!

I've gone over everything I can think of including the code within the sheet in question & the workbook code.

Anyone have any previous experience with this or suggestions?