From 90b393ed7953cd284ef7e22aa428dc7b5fa160ca Mon Sep 17 00:00:00 2001
From: Dan Stillman <dstillman@zotero.org>
Date: Wed, 8 Apr 2020 03:50:36 -0400
Subject: [PATCH] Fix Shift-drag/Cmd-drag to tag selector to remove tags

Apparently we implemented this 5 years ago in #873 and then broke it
(with the move to React, I think) without ever announcing it as a new
feature in Zotero 5? Anyway, this restores it, using Cmd on macOS (the
same as for moving vs copying items, or files in Finder).
---
 .../zotero/containers/tagSelectorContainer.jsx    | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/chrome/content/zotero/containers/tagSelectorContainer.jsx b/chrome/content/zotero/containers/tagSelectorContainer.jsx
index 4b633fc9ef..ce0f6b9d05 100644
--- a/chrome/content/zotero/containers/tagSelectorContainer.jsx
+++ b/chrome/content/zotero/containers/tagSelectorContainer.jsx
@@ -538,14 +538,13 @@ Zotero.TagSelector = class TagSelectorContainer extends React.PureComponent {
 				return;
 			}
 			
-			// Store the event, because drop event does not have shiftKey attribute set
-			Zotero.DragDrop.currentEvent = event;
 			elem.classList.add('dragged-over');
 			event.preventDefault();
-			event.dataTransfer.dropEffect = "copy";
+			// Don't show + cursor when removing tags
+			var remove = (Zotero.isMac && event.metaKey) || (!Zotero.isMac && event.shiftKey);
+			event.dataTransfer.dropEffect = remove ? "move" : "copy";
 		},
 		onDragExit: function (event) {
-			Zotero.DragDrop.currentEvent = null;
 			event.target.classList.remove('dragged-over');
 		},
 		onDrop: async function(event) {
@@ -564,6 +563,9 @@ Zotero.TagSelector = class TagSelectorContainer extends React.PureComponent {
 				return;
 			}
 			
+			// Remove tags on Cmd-drag/Shift-drag
+			var remove = (Zotero.isMac && event.metaKey) || (!Zotero.isMac && event.shiftKey);
+			
 			return Zotero.DB.executeTransaction(function* () {
 				ids = ids.split(',');
 				var items = Zotero.Items.get(ids);
@@ -571,9 +573,10 @@ Zotero.TagSelector = class TagSelectorContainer extends React.PureComponent {
 				
 				for (let i=0; i<items.length; i++) {
 					let item = items[i];
-					if (Zotero.DragDrop.currentEvent.shiftKey) {
+					if (remove) {
 						item.removeTag(value);
-					} else {
+					}
+					else {
 						item.addTag(value);
 					}
 					yield item.save();