diff --git a/piker/ui/_app.py b/piker/ui/_app.py
index 2743103e..3be073e7 100644
--- a/piker/ui/_app.py
+++ b/piker/ui/_app.py
@@ -178,8 +178,7 @@ def _main(
     tractor_kwargs,
 ) -> None:
     '''
-    Sync entry point to start a chart: a ``tractor`` + Qt runtime
-    entry point
+    Sync entry point to start a chart: a ``tractor`` + Qt runtime.
 
     '''
     run_qtractor(
diff --git a/piker/ui/_chart.py b/piker/ui/_chart.py
index aea1d927..a643c498 100644
--- a/piker/ui/_chart.py
+++ b/piker/ui/_chart.py
@@ -1365,4 +1365,12 @@ class ChartPlotWidget(pg.PlotWidget):
         self,
         key: str,
     ) -> Viz:
+        '''
+        Try to get an underlying ``Viz`` by key.
+
+        '''
         return self._vizs.get(key)
+
+    @property
+    def main_viz(self) -> Viz:
+        return self.get_viz(self.name)