Panels are widgets which can contain other widgets. As such, they are used for layout and only rarely have data associated with them directly - the DisclosurePanel for example, can have data in the header, and the TabPanel's tabs. Some are based on an HTML table element and some are based on a div. Here's a table of which are which.
| Panel Name | Type | Extends | Lets you |
|---|---|---|---|
| AbsolutePanel | DIV | ComplexPanel | Position widgets absolutely |
| CellPanel | TABLE | ComplexPanel | [Abstract] Subclass your own cell panels |
| ComplexPanel | - | Panel | [Abstract] Subclass panels with more than one widget |
| DeckPanel | DIV | ComplexPanel | Display widgets - one visible at a time |
| DisclosurePanel | TABLE | Composite | Show/hide a details pane |
| DockPanel | TABLE | CellPanel | Add widgets N, S, E, W around a central cell |
| FlowPanel | DIV | ComplexPanel | Add widgets as if to a normal DIV |
| FocusPanel | DIV | SimplePanel | Add focus to non-focusable widgets |
| FormPanel | DIV | SimplePanel | Submit a form to a server |
| Frame | IFRAME | - | Add an IFRAME to the application |
| HorizontalPanel | TABLE | CellPanel | Add a chain of cells horizontally |
| HorizontalSplitPanel | DIV | SplitPanel | Move the border between two cells |
| HTMLPanel | DIV | Add HTML, then access the elements that have IDs | |
| Panel | - | Widget | [Abstract] Base for all panels |
| ScrollPanel | DIV | SimplePanel | Stack child widgets, displaying contents of only one |
| StackPanel | TABLE | SimplePanel | Add a vertical chain of widgets |
| SimplePanel | DIV | Panel | [Abstract] One-widget panel |
| TabPanel | TABLE | VerticalPanel | Add virtual card-index dividers |
| VerticalPanel | TABLE | CellPanel | Add a chain of cells vertically |
| VerticalSplitPanel | DIV | SplitPanel | Move the border between two cells |