A rare problem can occur in Engauge - the Curve Geometry Info window or the Measure Geometry Info window may not appear when the appropriate Curve Geometry Info or Measure Geometry Info menu item is chosen (in the View menu).
This problem can arise when using dual monitors. The problem occurs when a window is dragged to the second monitor. That position is quietly saved by Engauge, and then eventually the user exits Engauge. Later, the second monitor is removed. The next time Engauge is started and a Curve or Measure Geometry Info window is selected, it will not seem to appear since it is automatically moved to the old position on the missing second monitor.
This problem could theoretically also occur when using a single monitor, by making drastic changes to the resolution.
The simple fix for this problem is to restart Engauge with the "-reset" command line option. Please note that this will cause all settings to be reset.