Allow dragging onto welcome text

chrome/content/zotero/xpcom/itemTreeView.js

@@ -1765,6 +1765,8 @@ Zotero.ItemTreeView.prototype._updateIntroText = function() {
 					};
 				}
 			}
+			
+			div.setAttribute('allowdrop', true);
 		}
 		// My Publications
 		else if (this.collectionTreeRow.isPublications()) {

chrome/content/zotero/xpcom/libraryTreeView.js

@@ -328,7 +328,17 @@ Zotero.LibraryTreeView.prototype = {
 		
 		var target = event.target;
 		if (target.tagName != 'treechildren') {
-			return false;
+			let doc = target.ownerDocument;
+			// Consider a drop on the items pane message box (e.g., when showing the welcome text)
+			// a drop on the items tree
+			let msgBox = doc.getElementById('zotero-items-pane-message-box');
+			if (msgBox.contains(target) && msgBox.firstChild.hasAttribute('allowdrop')) {
+				target = doc.querySelector('#zotero-items-tree treechildren');
+			}
+			else {
+				this._setDropEffect(event, "none");
+				return false;
+			}
 		}
 		var tree = target.parentNode;
 		let row = {}, col = {}, obj = {};

chrome/content/zotero/zoteroPane.xul

@@ -565,7 +565,10 @@
 
 							<!-- Label for displaying messages when items pane is hidden
 							 (e.g. "Advanced search mode — press Enter to search.")-->
-							<vbox id="zotero-items-pane-message-box" pack="center" align="center"/>
+							<vbox id="zotero-items-pane-message-box" pack="center" align="center"
+								ondragenter="return ZoteroPane.itemsView.onDragEnter(event)"
+								ondragover="return ZoteroPane.itemsView.onDragOver(event)"
+								ondrop="ZoteroPane.itemsView.onDrop(event); ZoteroPane.itemsView.drop(-1, -1, event.dataTransfer)"/>
 						</deck>
 					</vbox>