Application Toolbar
For general information about Explorer++’s toolbars, ie. moving, resizing, customizing, etc., see the toolbars Overview.

The Application toolbar shows a collection of your favorite applications; each button shows the application name and icon, if any. Buttons on the Application toolbar are similar to shortcuts to the applications themselves, providing instant access to your favorite tools. Unlike true Windows shortcuts, application toolbar buttons may have no parameters.
Open
Clicking this menu item opens the application (corresponding to the button, of course). This function is the same as clicking the button.
Tip
Files from the Files pane may be dragged-and-dro pped onto an application button to open them in that application. Selecting multiple files and using drag-and-drop will open all selected files, providing the application supports this behavior.
Example: multiple text files may be dragged-and-dropped onto the application button for a multi-tab text editor to open all files.
Delete
This menu item deletes the application button from the toolbar, with a confirmation dialog. It cannot be recovered.
Properties
This function opens the properties for the application shortcut and button. A dialog (Edit Application Button) is opened which is identical in function to the New Application Button, with all pertinent fields (for the button) already filled in. Fields may be edited from this dialog.
Tip
Re-ordering buttons on the toolbar (advanced - be careful!)
Application buttons are normally placed on the Application toolbar in the order they are created. Through judicious use of the Regedit application, they may be re-ordered.
open Regedit and navigate to
HKEY_CURRENT_USER\Software\Explorer++\ApplicationToolbar
select the ApplicationToolbar key in the left panel, and Export its contents to a suitable location using the context menu
edit the file to renumber the sub-keys (application buttons). They must always be numbered 0, 1, 2, etc. The first button is 0, the second is 1, and so on. The actual order they appear in (inside the file) is not important.
make sure Explorer++ is closed
Double-click on the edited file to re-enter the data into the registry.
That’s it!
A similar technique applies to using Explorer++ as a portable application - edit the config.xml file to re-order the application button lines. A number is not used; the order of the lines (under <ApplicationToolbar>) determines the button order.