1 files changed, 14 insertions, 1 deletions
diff --git a/src/client/views/collections/collectionSchema/CollectionSchemaView.tsx b/src/client/views/collections/collectionSchema/CollectionSchemaView.tsx
index 7fcac09dc..3de70ca2c 100644
--- a/src/client/views/collections/collectionSchema/CollectionSchemaView.tsx
+++ b/src/client/views/collections/collectionSchema/CollectionSchemaView.tsx
@@ -91,7 +91,7 @@ export class CollectionSchemaView extends CollectionSubView() {
     @observable _selectedCol: number = 0;
     @observable _selectedCells: Array<Doc> = []; 
     @observable _mouseCoordinates = { x: 0, y: 0 };
-    @observable _lowestSelectedIndex = -1;
+    @observable _lowestSelectedIndex = -1; //lowest index among selected rows; used to properly sync dragged docs with cursor position
     @observable _relCursorIndex = -1; //cursor index relative to the current selected cells
 
     // target HTMLelement portal for showing a popup menu to edit cell values.
@@ -410,6 +410,12 @@ export class CollectionSchemaView extends CollectionSubView() {
         return index;
     };
 
+    /**
+     * Calculates the relative index of the cursor in the group of selected rows, ie.
+     * if five rows are selected and the cursor is in the middle row, its relative index would be 2.
+     * Used to align actively dragged documents properly with the cursor.
+     * @param mouseY the initial Y position of the cursor on drag
+     */
     @action
     setRelCursorIndex = (mouseY: number) => {
         let rowHeight = CollectionSchemaView._rowHeight;
@@ -428,6 +434,7 @@ export class CollectionSchemaView extends CollectionSubView() {
         this._relCursorIndex = index;
     }
 
+    //Uses current mouse position to calculate the indexes of actively dragged docs
     findRowDropIndex = (mouseY: number) => {
         let index: number = 0;
         this.rowHeights.reduce((total, curr, i) => {
@@ -437,6 +444,12 @@ export class CollectionSchemaView extends CollectionSubView() {
             }
             return total + curr;
         }, CollectionSchemaView._rowHeight);
+
+        //fix index if selected rows are dragged out of bounds
+        if (index <= 0) index = 1 
+        let maxY = this.rowHeights.reduce((total, curr) => total + curr, 0) + CollectionSchemaView._rowHeight;
+        if (mouseY > maxY) index = this.childDocs.length - 1;
+
         return index - this._relCursorIndex;
     };