Automatically Expand Paths of single children #1063

In these cases, I expect all folders to open recursively
when clicking on com.wittmaxi.plugin

com.wittmaxi.plugin
 └─src
    └─org.foo.com
       └─Bar.java

A new feature in SWT allows for this feature, this PR enables that
feature in the Package Explorer.

Implements
eclipse-platform/eclipse.platform.ui#1063

org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/packageview/PackageExplorerPart.java

@@ -250,12 +250,20 @@ public void treeExpanded(TreeExpansionEvent event) {
 
 
  private class PackageExplorerProblemTreeViewer extends ProblemTreeViewer {
+ /**
+ * Number of levels to automatically expand when an element only has a single
+ * child.
+ *
+ * @see AbstractTreeViewer#setAutoExpandOnSingleChildLevels(int)
+ */
+ private static final int AUTO_EXPAND_ON_SINGLE_CHILD_LEVELS= 10;
  // fix for 64372 Projects showing up in Package Explorer twice [package explorer]
  private final List<Object> fPendingRefreshes;
 
  public PackageExplorerProblemTreeViewer(Composite parent, int style) {
  super(parent, style);
  fPendingRefreshes= Collections.synchronizedList(new ArrayList<>());
+ setAutoExpandOnSingleChildLevels(AUTO_EXPAND_ON_SINGLE_CHILD_LEVELS);
  }
  @Override
  public void add(Object parentElement, Object... childElements) {