OnClick event

OnClick fires after the standard OnMouseDown / OnMouseUp sequence whenever the user presses and releases the left mouse button without moving the cursor far enough to register as a drag. The Sender parameter is the TPdfView instance itself; the cursor position is not passed, but it can be retrieved from Mouse.CursorPos and translated with ScreenToClient.

The viewer's internal click handling for annotations, web links and form fields runs before this event — if the click hit a navigable link the page jump or URI launch has already happened. OnClick is therefore most useful for application-level reactions: dismissing a tool-tip overlay, hiding a thumbnail panel, recording an analytics event, or toggling a focus mode.

If a granular position is needed, hook OnMouseDown or OnMouseUp instead. To detect clicks on specific PDF objects (annotations, links, form fields), use the dedicated events OnAnnotationLinkClick and OnWebLinkClick, or call HasFormFieldAt from OnMouseDown.

• Design-time assignable in the Object Inspector or at run-time by code. Persisted as a method reference in the form file.
• VCL and LCL share the same firing rules; the LCL also generates OnClick when the user presses Enter while the viewer holds focus (consistent with other TWinControl descendants).
• Disabled by Enabled := False — the event does not fire when the viewer is in read-only preview mode.
• Avoid heavy work in the handler; queue background actions through TThread.Queue if you need to perform I/O so the click feels responsive.