In the KendoToolBar item configuration, there is currently a property called "overflow". The values of this property are: "never", "always", and "auto" (default). If the item.overflow value is set to "never" then the item remains in the toolbar and is not added to the overflow menu when the window shrinks. If the value is set to "always" or "auto", then the item is displayed in the overflow menu. The problem, however, is that sometimes you may want a toolbar item to disappear when the page shrinks, but you don't want or need it in the overlow menu.
A specific example is a toolbar item of type "separator". When the separator item.overflow is set to "auto", it adds a gap in the overflow menu between other items. I don't want this gap. Therefore, I set the separator item.overflow to "never". Unfortunately, this means that the separator remains on the toolbar. In the case where I have several separators in the toolbar with overflow set to "never", these all just stack up next to each other in the toolbar as the window is shrunk. I want them to disappear, but also not show up in the overflow menu. An overflow value of "hidden" could solve this problem.