{ Options Help - Action Modes }
{ Choosing different "action modes" in XPVM controls what functions }
{ are executed when the user clicks the Left mouse button in either }
{ the Space-Time or Utilization View canvas. }
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{ There are currently two different action modes: }
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{         "Query"  and  "Correlate" }
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{ In standard "Query" mode the clicks in the Space-Time View are }
{ interpreted normally, to query individual task state rectangles }
{ or message lines (see the online help for "Views/Space-Time"). }
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{ The "Correlate" mode allows the user to "go back in time" and see }
{ what the views looked like at any specific moment.  By clicking }
{ the Left mouse button in either the Space-Time or Utilization }
{ View canvas, the user selects a "correlate time."  Then the }
{ Network, Message Queue and Call Trace Views are "correlated" }
{ to that time and redrawn. }
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{ The "correlate time" can be moved back and forth by sliding the }
{ mouse with the Left mouse button held down, and the correlation }
{ can be temporarily "locked in" by double-clicking.  After this }
{ double-clicking, the user can use standard queries to explore }
{ the locked state for each of the correlated views.  The lock }
{ is released by clicking again with the Left mouse button in }
{ either the Space-Time or Utilization View canvas. }
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{ The "Correlate" mode is especially handy for reviewing the }
{ behavior of the user's application, back and forth over time. }
{ The information presented while in "Correlate" mode also tends }
{ to be more accurate than that provided by normal trace play. }
{ Events often trickle in over networks out of order (from task }
{ to task) resulting in misleading view information.  But in the }
{ "Correlate" mode, queries have the benefit of 20/20 hindsight }
{ to view exactly what the state of the system was at the given }
{ time, independent of whether the trace events arrived in }
{ chronological order. }
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