fix: center active mode in selector dropdown on open (#7883)

Co-authored-by: Roo Code <[email protected]>
Co-authored-by: daniel-lxs <[email protected]>

webview-ui/src/components/chat/ModeSelector.tsx

@@ -44,6 +44,8 @@ export const ModeSelector = ({
 	const [open, setOpen] = React.useState(false)
 	const [searchValue, setSearchValue] = React.useState("")
 	const searchInputRef = React.useRef<HTMLInputElement>(null)
+	const selectedItemRef = React.useRef<HTMLDivElement>(null)
+	const scrollContainerRef = React.useRef<HTMLDivElement>(null)
 	const portalContainer = useRooPortal("roo-portal")
 	const { hasOpenedModeSelector, setHasOpenedModeSelector } = useExtensionState()
 	const { t } = useAppTranslation()
@@ -149,10 +151,37 @@ export const ModeSelector = ({
 		[trackModeSelectorOpened],
 	)
 
-	// Auto-focus search input when popover opens.
+	// Auto-focus search input and scroll to selected item when popover opens.
 	React.useEffect(() => {
-		if (open && searchInputRef.current) {
-			searchInputRef.current.focus()
+		if (open) {
+			// Focus search input
+			if (searchInputRef.current) {
+				searchInputRef.current.focus()
+			}
+
+			requestAnimationFrame(() => {
+				if (selectedItemRef.current && scrollContainerRef.current) {
+					const container = scrollContainerRef.current
+					const item = selectedItemRef.current
+
+					// Calculate positions
+					const containerHeight = container.clientHeight
+					const itemTop = item.offsetTop
+					const itemHeight = item.offsetHeight
+
+					// Center the item in the container
+					const scrollPosition = itemTop - containerHeight / 2 + itemHeight / 2
+
+					// Ensure we don't scroll past boundaries
+					const maxScroll = container.scrollHeight - containerHeight
+					const finalScrollPosition = Math.min(Math.max(0, scrollPosition), maxScroll)
+
+					container.scrollTo({
+						top: finalScrollPosition,
+						behavior: "instant",
+					})
+				}
+			})
 		}
 	}, [open])
 
@@ -223,36 +252,40 @@ export const ModeSelector = ({
 					)}
 
 					{/* Mode List */}
-					<div className="max-h-[300px] overflow-y-auto">
+					<div ref={scrollContainerRef} className="max-h-[300px] overflow-y-auto">
 						{filteredModes.length === 0 && searchValue ? (
 							<div className="py-2 px-3 text-sm text-vscode-foreground/70">
 								{t("chat:modeSelector.noResults")}
 							</div>
 						) : (
 							<div className="py-1">
-								{filteredModes.map((mode) => (
-									<div
-										key={mode.slug}
-										onClick={() => handleSelect(mode.slug)}
-										className={cn(
-											"px-3 py-1.5 text-sm cursor-pointer flex items-center",
-											"hover:bg-vscode-list-hoverBackground",
-											mode.slug === value
-												? "bg-vscode-list-activeSelectionBackground text-vscode-list-activeSelectionForeground"
-												: "",
-										)}
-										data-testid="mode-selector-item">
-										<div className="flex-1 min-w-0">
-											<div className="font-bold truncate">{mode.name}</div>
-											{mode.description && (
-												<div className="text-xs text-vscode-descriptionForeground truncate">
-													{mode.description}
-												</div>
+								{filteredModes.map((mode) => {
+									const isSelected = mode.slug === value
+									return (
+										<div
+											key={mode.slug}
+											ref={isSelected ? selectedItemRef : null}
+											onClick={() => handleSelect(mode.slug)}
+											className={cn(
+												"px-3 py-1.5 text-sm cursor-pointer flex items-center",
+												"hover:bg-vscode-list-hoverBackground",
+												isSelected
+													? "bg-vscode-list-activeSelectionBackground text-vscode-list-activeSelectionForeground"
+													: "",
 											)}
+											data-testid="mode-selector-item">
+											<div className="flex-1 min-w-0">
+												<div className="font-bold truncate">{mode.name}</div>
+												{mode.description && (
+													<div className="text-xs text-vscode-descriptionForeground truncate">
+														{mode.description}
+													</div>
+												)}
+											</div>
+											{isSelected && <Check className="ml-auto size-4 p-0.5" />}
 										</div>
-										{mode.slug === value && <Check className="ml-auto size-4 p-0.5" />}
-									</div>
-								))}
+									)
+								})}
 							</div>
 						)}
 					</div>