What makes toolbar menus "leap frog"?

[ChrisGreaves]

3.png

I have a chunk of VBA code that re-arranges toolbar controls; it works most of the time.
This morning I decided to investigate its behaviour, and thought to start off with all controls arranged in sequence ("BestFitToolbarsByName" is supposed to do just that, so I'm curious if it can do it consistently when the toolbars are already in sequence).

(1) If I use the mouse to drag "Infor" about 1/2 cm to the left, it leap-frogs Indxr and sits next to Catal.
(2) If I start at the LHS and drag Calen to be snug against WbWrd, no leap-frogging takes place; I can work rightwards and continue successfully with Catal, Indxr, Infor.
(3) Interrupting the sequence by selecting a text position, keying in text, then returning to drag does not inhibit leap-frogging.
(4) Leapfrogging occurs rightwards, too. If I try to drag the second control to the right, it shunts all its neighbours for a while, then decides to leap-frog.
(5) I am close to a conclusion that dragging a control effects a shunting motion until the control has passed outside its original zone, at which point shunting stops and moving begins; which I interpret as leap-frogging. That is, the distinction is made at the left-to-right width of the control.

[HansV]

The problem will become irrelevant sooner or later. The ribbon introduced in Office 2007 doesn't offer this degree of customization...