working on todo.md features

docs/USER-GUIDE.md

@@ -65,6 +65,12 @@ window change moves the trigger with it.
 - **Ctrl+drag** frames x to a box, **Alt+drag** y.
 - **Fit to data** (menu) auto-scales both axes and frames the whole buffered range.
 
+Each plot has its own **right-click menu**, in the same compact row style as the app's menu:
+**Y axis: auto scale**, **Y axis: fixed range...**, **Fit X axis**, **Fit all** (`f`), and
+**Remove signal** — which swaps the menu to one entry per trace on that plot plus *All traces on
+this plot*, with a **Back** row to return. That is how a trace comes off a row without going through
+the layout editor.
+
 The view is bounded by the **time window**, not by the buffer: zooming out stops at the span you set,
 and panning stops where the data starts. When the buffer holds *less* than the window — right after a
 signal is enabled — the window is left empty on its left, which is what a scope that has just started