How to change icon for a reappearing app. in my quicklaunch?

Try to hide that icon.

Also you can to use the your own folder as toolbar folder: Create the folder somewhere on HDD, open TLB Settings->Toolbars and add this folder as new toolbar. Backup your current toolbar, right-click TLB, select Switch toolbar and click the created toolbar name. Restore the toolbar from the backup. Now TLB uses own folder for shortcuts. As this is non standart quick launch bar folder, you don't see the icons other programs can write into the standard place.