For me, the extra tab that was hiding came from the Podcasts extension. When added to the notebook, this had the property Order = 40, which duplicated the Order value of a previous page in the notebook. I have submitted a patch to the banshee bug that determines the amount of visible pages by counting the unique page.Order values, and calls notebook.ShowTabs when there is only one visible page.
For me, the extra tab that was hiding came from the Podcasts extension. When added to the notebook, this had the property Order = 40, which duplicated the Order value of a previous page in the notebook. I have submitted a patch to the banshee bug that determines the amount of visible pages by counting the unique page.Order values, and calls notebook.ShowTabs when there is only one visible page.