Toolbar height jumping

Hello. is there a way to avoid this annoying lister's size change (more precisely, the height of the menu button) when switching from source to dest, if one lister displays thumbnails and the other does not.

P.S. i just changed one of the button's size to "large" - that's the solution)

The icon for the button that's appearing must be larger than the other icons on the toolbar.

Is that iconset not the standard 32px. If so then placing a 1px wide search field (Insert new label then change field type to seach and edit the name to nothing) will do the trick, leaves a visible line but stops the toolbar height adjusting.