/mdn2/en-US/docs/Mozilla/Add-ons/WebExtensions/API/devtools/panelspanels
create elements ElementsPanel ExtensionPanel ExtensionSidebarPane onThemeChanged themeName
/mdn2/en-US/docs/Mozilla/Add-ons/WebExtensions/API/devtools/panels/ElementsPanelElementsPanel
createSidebarPane onSelectionChanged
/mdn2/en-US/docs/Mozilla/Add-ons/WebExtensions/API/devtools/panels/ElementsPanel/createSidebarPanecreateSidebarPane
/mdn2/en-US/docs/Mozilla/Add-ons/WebExtensions/API/devtools/panels/ExtensionSidebarPaneExtensionSidebarPane
onHidden onShown setExpression setObject setPage