A control that handles some very basic uses of the CSS Flexible Box Layout Module, a.k.a. "flexbox". When flexbox support is not available, or in situations where it is known to be buggy, the control falls back to simpler styling solutions or manual layout. This control is primarily used as a base class for the HorizontalPanels and VerticalPanels controls, rather than being used directly.

There are many strategies for laying out a content area with top/bottom or left/right panels, but most of these assume that the side panels have a known, fixed height or width (respectively). The SimpleFlexBox control works with panels whose content size is not determined until runtime.

This control is a "polyfill", meant to enable use of layout features which are not yet available in all browsers. For simplicity, the control assumes a maximum of one panel to either side of the main content panel. I.e., in horizontal orientation, there can be up to one left panel and one right panel; in vertical orientation, there can be up to one top panel and one bottom panel.

This control was discussed in a user interface blog post.