Created attachment 163519 [details]
Gnumeric file with Sheet 3 hidden

When a file with hidden sheets is opened, and those sheets are unhidden, they are not displayed when the sheet's tab is selected.

Steps to reproduce:
1) Open a gnumeric file that contains a hidden sheet
2) Select Edit -> Sheet -> Manage sheets...
3) Click on the visibility column of the hidden sheet, and observe that the hidden sheet's tab is displayed at the bottom of the display.
4) Close the Mange sheets... dialog
5) Select the unhidden sheet, and observe that when it is selected, the previously selected sheet is still displayed.

It seems as though that when the hidden sheet's tab is added to the display, the callback to display the sheet that it represents is not being assigned to the tab.

A work around is to unhide the sheet, save the file, close and re-open it, after which the sheet is visible.

I have attached a gnumeric file with a hidden sheet that illustrates the above buggy behaviour.