Don't allow dropping a bucket in another bucket

src/views/list/views/Kanban.vue

@@ -19,13 +19,13 @@
 		<div :class="{ 'is-loading': loading && !oneTaskUpdating}" class="kanban kanban-bucket-container loader-container">
 			<draggable
 				v-model="buckets"
-				@start="() => drag = true"
+				@start="() => dragBucket = true"
 				@end="updateBucketPosition"
 				group="buckets"
 				v-bind="dragOptions"
 				:disabled="!canWrite"
 			>
-				<transition-group type="transition" :name="!drag ? 'move-bucket': null" tag="div" class="kanban-bucket-container">
+				<transition-group type="transition" :name="!dragBucket ? 'move-bucket': null" tag="div" class="kanban-bucket-container">
 					<div
 						:key="`bucket${bucket.id}`"
 						class="bucket"
@@ -124,7 +124,7 @@
 								v-model="bucket.tasks"
 								@start="() => drag = true"
 								@end="updateTaskPosition"
-								:group="{name: 'tasks', put: shouldAcceptDrop(bucket)}"
+								:group="{name: 'tasks', put: shouldAcceptDrop(bucket) && !dragBucket}"
 								v-bind="dragOptions"
 								:disabled="!canWrite"
 								:data-bucket-index="k"
@@ -249,6 +249,7 @@ export default {
 	data() {
 		return {
 			drag: false,
+			dragBucket: false,
 			dragOptions: {
 				animation: 150,
 				ghostClass: 'ghost',
@@ -491,6 +492,7 @@ export default {
 				})
 		},
 		updateBucketPosition(e) {
+			this.dragBucket = false
 			console.log('drop bucket', e)
 		},
 		setBucketLimit(bucket) {