My goal is to move all tasks in one folder to another then delete the old folder. I'll not mention (again) how nice it would be to be able to do this with a bulk change as this feature has been suggested under separate cover). Steps used:
-View by folder
-Click on the appropriate folder tab
-For each task, change the folder name.
-When done, note that you get the "You've changed them all" message so Toodledo knows that all tasks have been moved from the folder
-Click Folders from the left navigator (Folders & Contexts)
-Why does the folder you are about to delete show the number of tasks > 0?