diff --git a/src/components/ThumbnailCanvasGrouping.js b/src/components/ThumbnailCanvasGrouping.js
index cc966ff815eba1093a823238a750ce70f5ac309c..72f08bb4a3479bf7060b5ed174952e8eca3cefe8 100644
--- a/src/components/ThumbnailCanvasGrouping.js
+++ b/src/components/ThumbnailCanvasGrouping.js
@@ -44,7 +44,7 @@ export class ThumbnailCanvasGrouping extends PureComponent {
           ...style,
           boxSizing: 'content-box',
           height: (Number.isInteger(style.height)) ? style.height - SPACING : null,
-          left: style.left + SPACING,
+          left: (Number.isInteger(style.left)) ? style.left + SPACING : null,
           top: style.top + SPACING,
           width: (Number.isInteger(style.width)) ? style.width - SPACING : null,
         }}