Logical AND needed

[scuniff]

https://github.com/ome/omero-insight/blob/21b72187f896c36e356dfa6c4c3116bc4b633ba2/src/main/java/org/openmicroscopy/shoola/agents/treeviewer/browser/BrowserControl.java#L328

Regarding the if statement:

                List<?> l = display.getChildrenDisplay();
                if (l != null & l.size() > 0) {
                    view.expandNode((TreeImageDisplay) l.get(0), true);
                }

If variable l is null then there will be a NPE when l.size() is executed

I think logical AND && is needed

                List<?> l = display.getChildrenDisplay();
                if (l != null && l.size() > 0) {
                    view.expandNode((TreeImageDisplay) l.get(0), true);
                }

[jburel]

Fixed in #419