I've created a few custom folders on my home screens, & have added shortcuts to them. Suddenly, I'm unable to add anything new to these folders! I tried opening the folder, pressing on an empty space, & nothing comes up. I've tried opening the folder & tapping the menu button. There is an option for "add" but it's grayed out & won't let me select it. The folders just have a few icons in each folder so I should be able to add more. What am I doing wrong??