The ToolTip is available for the following elements:
the calendar events (default value is taken from DataTextField but you can change it using BeforeEventRender)
the resource headers in DayPilotScheduler (you can change it by setting ToolTip property for each resource)
the column headers in DayPilotCalendar - for both ViewType="Resources" and ViewType="Days" (you can modify using ToolTip property of the Columns collection items, it's similar to resources in DayPilotScheduler)
the time headers in DayPilotScheduler (you can modify it using BeforeTimeHeaderRender handler)
These standard tooltips are simply transformed into title="" attributes and they should respect RTL text orientation.
It's also possible to replace the event tooltips with DayPilotBubble by assigning BubbleID property. I haven't tested it but I believe you can use <div style='direction:rtl'>your text</div> as your InnerHTML in RenderContent event handler to switch to RTL rendering.
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