Annot:    Option:   Span labels:   View:    Search: usec: ..
⊕ Shift-click 1-4 to save, click to restore. Axes: scroll wheel to zoom, drag to pan. Items: shift-click-unclick to annotate. Shift-click-unshift to keep, shift-drag to measure. Red dot resets. [more]
   +------------------------------------------------------------------------+
   |            (0) UI controls (HTML)                                      |
   +------------------------------------------------------------------------+
   |            (1) Title                                                   |
   +----+--------------------------------------------------------------+----+
   |(2) |                                                              |(4) |
   |Y-  |       (3) Main SVG drawing area                              |IPC |
   |axis|                                                              |    |
   |    |                                                              |    |
   +----+--------------------------------------------------------------+----+
   |            (5) X-axis                                                  |
   +----+--------------------------------------------------------------+----+
   |            (6) UI hint text (HTML)                                     |
   +----+--------------------------------------------------------------+----+

   List of UI active areas
   In general, click toggles buttons while shift-click cycles through more choices
   In general, shift-click-unclick to annotate/highlight; shift-click-unshift to 
     keep multiple results onscreen at once

   (0) Text and buttons
     User annotate PID names	 off/on
     All  annotate all items	 off/on

     Mark mark_x events	 	 off/both/text/numbers
     Arc  wakeup arcs		 off/on
     Lock lock-held lines	 off/on
     Slow CPU clock freq	 off/gradient
     IPC  instructions per cycle off/both/user/kernel
     Samp PC samples		 off/on
     CB   color blind colors	 off/on
     Filter searchable PID/thread, CPU, and PC-symbol selections
     View Active spans		 show only CPU/PID lanes with spans in the time window
     View Viewable PIDs	 show viewable PID spans and only their associated CPUs
     View Boundary spans	 show only entries whose start or end is in the time window
     I				 open Filter and focus its last-used control
     Esc			 close Filter without clearing it
     U				 open Advanced span search across the full timeline
     Advanced span search	 regex results; arrows jump, Overview frames all matches
     Filter matching spans	 draw only spans returned by the advanced regex
     Esc			 close Advanced span search without clearing it
     H				 open time-view history
     J / K			 previous / forward time view
     Share view			 copy a trace-specific link to this exact saved state
     Export subset		 choose a time window and download smaller JSON or standalone HTML
     O / Reset Y		 reset vertical shift and zoom only
     Span labels - / % / +	 decrease, reset, or increase span-name text
     Filter/Search/History	 drag by title; resize from the lower-right corner

     Search:    regex string match 
     !	        invert search	 off/on, like grep -v
     usec:      match only event duration in [lo..hi]
  
   (1) Title	text size	1.0/1.25/1.50/0.75 times default
  
   (2) Y-axis group triangles	collapse/expand/gray=one-fourth/gray=one-twentieth
       Y-axis labels		mouse and wheel to pan/zoom vertically
       Y-axis labels		shift-click:normal/highlight
  
   (3) anywhere 		mouse and wheel to pan/zoom horizontally	
     Red dot 			resets display
     Yellow overlay indicates slow CPU clock rate (power saving)
     Overlapping duration spans stack downward inside their existing row

   (5) Basetime date		normal/relative to row start
  
   (6) Buttons
     1 2 3 4 5			shift-click:save, click:restore current view
     double-arrow		toggles between last two views
     [more]			this text off/on

International Morse Code (for wait events)
  A    .-    B    -...  Cpu  -.-.  Disk -.. 
  E    .     F    ..-.  G    --.   H    ....
  I    ..    J    .---  tasK -.-   Lock .-..
  Mem  --    Net  -.    O    ---   Pipe .--.
  Q    --.-  R    .-.   Sche ...   Time -   
  U    .. -  V    ...-  W    .--   X    -..-
  Y    -.--  Z    --..