diff --git a/fsl/fsleyes/displaycontext/lightboxopts.py b/fsl/fsleyes/displaycontext/lightboxopts.py
index 4b3fdbb9bcc889fc24bd8766fc73a6bbe8af23b4..30f3bf9a40db652f7f7cc9b1facc28e5943ac873 100644
--- a/fsl/fsleyes/displaycontext/lightboxopts.py
+++ b/fsl/fsleyes/displaycontext/lightboxopts.py
@@ -22,3 +22,7 @@ class LightBoxOpts(sceneopts.SceneOpts):
     zrange         = copy.copy(canvasopts.LightBoxCanvasOpts.zrange)
     showGridLines  = copy.copy(canvasopts.LightBoxCanvasOpts.showGridLines)
     highlightSlice = copy.copy(canvasopts.LightBoxCanvasOpts.highlightSlice)
+
+    def __init__(self, *args, **kwargs):
+        sceneopts.SceneOpts.__init__(self, *args, **kwargs)
+        self.setConstraint('zoom', 'minval', 10)