From 212882a5a58fdafef4dae54da61bb96f41a3e486 Mon Sep 17 00:00:00 2001
From: Tyler Goodlet <jgbt@protonmail.com>
Date: Thu, 20 May 2021 16:10:42 -0400
Subject: [PATCH] Don't try to show xhair if no active plot

---
 piker/ui/_chart.py            | 1 +
 piker/ui/_graphics/_cursor.py | 7 ++++++-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/piker/ui/_chart.py b/piker/ui/_chart.py
index 32743cfb..be5aaf7a 100644
--- a/piker/ui/_chart.py
+++ b/piker/ui/_chart.py
@@ -172,6 +172,7 @@ class ChartSpace(QtGui.QWidget):
 
             # XXX: pretty sure we don't need this
             # remove any existing plots?
+            # XXX: ahh we might want to support cache unloading..
             # self.vbox.removeWidget(self.linkedcharts)
 
         # switching to a new viewable chart
diff --git a/piker/ui/_graphics/_cursor.py b/piker/ui/_graphics/_cursor.py
index 159c773e..0919f6f9 100644
--- a/piker/ui/_graphics/_cursor.py
+++ b/piker/ui/_graphics/_cursor.py
@@ -435,7 +435,12 @@ class Cursor(pg.GraphicsObject):
         self,
         y_label_level: float = None,
     ) -> None:
-        g = self.graphics[self.active_plot]
+
+        plot = self.active_plot
+        if not plot:
+            return
+
+        g = self.graphics[plot]
         # show horiz line and y-label
         g['hl'].show()
         g['vl'].show()