I think I've got a waterfall feature working in StripTool! Yay! The waterfall amount at any given time is stored in a variable within StripToolPlot. This class also handles implementing the waterfall as an offset to MPlotAbstractItem. The waterfall amount can be set by the user via QDoubleSpinBox in StripToolControlPanel. The signal from the entry widget is forwarded through the control panel and model until it reaches StripToolPlot. I think what is displayed is consistent with conventional waterfall behavior, but I'm not entirely sure. Will look this over again next time. What I'd like to work on next is the ability to specify upper and lower limits on the scale displayed for a particular pv. I've started working on this (the input is through EditPVDialog) but it's not complete, and the widgets are currently disabled.