Bug 158778 [Viewers] request for remove(parent, index) API on tree viewer
3.3 It would be helpful to have a 'remove(Object parent, int index)' method on the tree viewer to complement that 'replace(...)' and 'setChildCount(...)' APIs. The debug platform requires such a method to implement filtering in virtual tree views. Rather than performing a 'replace/remove' based on elements, the content provider can make one atomic call to remove an element at a specific index.
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/TreeViewer.java
return ((TreeItem) item).getBounds(columnNumber);
			}
			int getColumnCount() {
				return getTree().getColumnCount();
			}
			Item[] getSelection() {
				return getTree().getSelection();
			}
			void setEditor(Control w, Item item, int columnNumber) {
				treeEditor.setEditor(w, (TreeItem) item, columnNumber);
			}
			void setSelection(IStructuredSelection selection, boolean b) {
				TreeViewer.this.setSelection(selection, b);
			}
			void showSelection() {
				getTree().showSelection();
			}
			void setLayoutData(CellEditor.LayoutData layoutData) {
				treeEditor.grabHorizontal = layoutData.grabHorizontal;
				treeEditor.horizontalAlignment = layoutData.horizontalAlignment;
				treeEditor.minimumWidth = layoutData.minimumWidth;
			}
			void handleDoubleClickEvent() {
				Viewer viewer = getViewer();
				fireDoubleClick(new DoubleClickEvent(viewer, viewer
						.getSelection()));
				fireOpen(new OpenEvent(viewer, viewer.getSelection()));
			}
		};
	}