I'm using ExtJS 3.2 and have content inside of a tab panel, and the tab panel inside of a container in a Viewport. The actual TabPanel resizes correctly on the viewport size changes, but the content inside a panel in the TabPanel seems to be a fixed width and will not shrink when the window is resized.The strange thing is it grows if I increase the window size. How can I get the content inside a Tabpanel to shrink on window resizing. Sorry for this being confusing, my structure is this: Viewport (rendered to body, and sets defaults {monitorResize:true}) - Text Label - TabPanel - Tab - Container (Border Layout) - Panel 1 (Center) - Panel 2 (East) - Panel 3 (South) Thanks in advance!