fix: more accurate initial heigth for VirtualElements + fallback fix in VirtualElement

Author: olzzon

packages/webui/src/client/lib/VirtualElement.tsx

@@ -338,18 +338,22 @@ export function VirtualElement({
 		>
 			<div
 				ref={setRef}
+				id={id}
 				style={
-					// We need to set undefined if the height is not known, to allow the parent to calculate the height
+					// Use measurements if available, otherwise fall back to placeholder/ref height when virtualized
 					measurements
 						? {
 								height: measurements.clientHeight + 'px',
 						  }
+						: !isShowingChildren
+						? {
+								height: ((placeholderHeight || ref?.clientHeight) ?? 0) + 'px',
+						  }
 						: undefined
 				}
 			>
 				{!isShowingChildren ? (
 					<div
-						id={measurements?.id ?? id}
 						className={`virtual-element-placeholder ${placeholderClassName}`}
 						style={styleObj}
 					></div>

packages/webui/src/client/ui/RundownView.tsx

@@ -2730,6 +2730,27 @@ const RundownViewContent = translateWithTracker<IPropsWithReady, IState, ITracke
 								const isLastSegment =
 									rundownIndex === rundownArray.length - 1 && segmentIndex === segmentArray.length - 1
 
+								// Calculate placeholder height based on segment properties
+								const calculatePlaceholderHeight = (segment: DBSegment): number => {
+									// Base height for a normal segment timeline
+									const BASE_SEGMENT_HEIGHT = 260
+									// Approximate height for dashboard panel (mini-shelf) when displayed
+									const DASHBOARD_PANEL_HEIGHT = 200
+									// Minimum height for hidden segments to prevent layout issues
+									const HIDDEN_SEGMENT_MIN_HEIGHT = 10
+
+									if (segment.isHidden) {
+										// Hidden segments don't render the timeline at all
+										// They only render the dashboard panel if showShelf is true
+										return segment.showShelf ? DASHBOARD_PANEL_HEIGHT : HIDDEN_SEGMENT_MIN_HEIGHT
+									}
+
+									// Normal segment: base timeline height + optional dashboard panel
+									return segment.showShelf ? BASE_SEGMENT_HEIGHT + DASHBOARD_PANEL_HEIGHT : BASE_SEGMENT_HEIGHT
+								}
+
+								const segmentPlaceholderHeight = calculatePlaceholderHeight(segment)
+
 								return (
 									<ErrorBoundary key={unprotectString(segment._id)}>
 										<VirtualElement
@@ -2739,8 +2760,8 @@ const RundownViewContent = translateWithTracker<IPropsWithReady, IState, ITracke
 											})}
 											id={SEGMENT_TIMELINE_ELEMENT_ID + segment._id}
 											margin={'100% 0px 100% 0px'}
-											initialShow={globalIndex++ < window.innerHeight / 260}
-											placeholderHeight={260}
+											initialShow={globalIndex++ < window.innerHeight / segmentPlaceholderHeight}
+											placeholderHeight={segmentPlaceholderHeight}
 											placeholderClassName="placeholder-shimmer-element segment-timeline-placeholder"
 											width="auto"
 										>