Version 8.5 had a Move Up button in Form > Panel Operations > Edit Toolbar that allowed you to change a buttons sequence in the toolbar.

In Version 8.6 this button is not visible?

There are also Up and Down buttons in the preceding Form > Panel Operations screen but they do not seem to influence the sequence of buttons in the published actual form.

The loss of the Move Up button means if you want to change the sequence of buttons you need to delete the buttons then re-created them all...unless I'm missing something?