Merge pull request #14418 from meeseeksmachine/auto-backport-of-pr-14285-on-v3.1.0-doc

timhoffm · web-flow · commit 28425365a74f · 2019-06-02T21:53:59.000+02:00
Backport PR #14285 on branch v3.1.0-doc (DOC: add note to example about keeping hard-ref to SpanSelector)
diff --git a/examples/widgets/span_selector.py b/examples/widgets/span_selector.py
@@ -38,9 +38,17 @@ def onselect(xmin, xmax):
     ax2.set_ylim(thisy.min(), thisy.max())
     fig.canvas.draw()
 
-# Set useblit=True on most backends for enhanced performance.
+#############################################################################
+# .. note
+#
+#    If the SpanSelector object is garbage collected you will lose the
+#    interactivity.  You must keep a hard reference to it to prevent this.
+#
+
+
 span = SpanSelector(ax1, onselect, 'horizontal', useblit=True,
                     rectprops=dict(alpha=0.5, facecolor='red'))
+# Set useblit=True on most backends for enhanced performance.
 
 
 plt.show()
