chore: position insertion marker in a single function

core/block_svg.ts

@@ -1515,38 +1515,13 @@ export class BlockSvg
    * or an insertion marker.
    *
    * @param sourceConnection The connection on the moving block's stack.
-   * @param targetConnection The connection that should stay stationary as this
-   *     block is positioned.
+   * @param originalOffsetToTarget The connection original offset to the target connection
+   * @param originalOffsetInBlock The connection original offset in its block
    * @internal
    */
   positionNearConnection(
     sourceConnection: RenderedConnection,
-    targetConnection: RenderedConnection,
-  ) {
-    // We only need to position the new block if it's before the existing one,
-    // otherwise its position is set by the previous block.
-    if (
-      sourceConnection.type === ConnectionType.NEXT_STATEMENT ||
-      sourceConnection.type === ConnectionType.INPUT_VALUE
-    ) {
-      const dx = targetConnection.x - sourceConnection.x;
-      const dy = targetConnection.y - sourceConnection.y;
-
-      this.moveBy(dx, dy);
-    }
-  }
-
-  /**
- * Reposition a block after its connection has been resized, to match exactly the target block position.
- * The block to position is usually either the first block in a dragged stack
- * or an insertion marker.
- *
- * @param sourceConnection The connection on the moving block's stack.
- * @param originalOffsetInBlock The connection original offset in its block, before the resize occured
- * @internal
- */
-  repositionAfterConnectionResize(
-    sourceConnection: RenderedConnection,
+    originalOffsetToTarget: {x: number; y: number},
     originalOffsetInBlock: Coordinate,
   ) {
     // We only need to position the new block if it's before the existing one,
@@ -1555,8 +1530,12 @@ export class BlockSvg
       sourceConnection.type === ConnectionType.NEXT_STATEMENT ||
       sourceConnection.type === ConnectionType.INPUT_VALUE
     ) {
-      const dx = originalOffsetInBlock.x - sourceConnection.getOffsetInBlock().x;
-      const dy = originalOffsetInBlock.y - sourceConnection.getOffsetInBlock().y;
+      // First move the block to match the orginal target connection position
+      let dx = originalOffsetToTarget.x;
+      let dy = originalOffsetToTarget.y;
+      // Then adjust its position according to the connection resize
+      dx +=  originalOffsetInBlock.x - sourceConnection.getOffsetInBlock().x;
+      dy +=  originalOffsetInBlock.y - sourceConnection.getOffsetInBlock().y;
 
       this.moveBy(dx, dy);
     }

core/insertion_marker_manager.ts

@@ -611,16 +611,16 @@ export class InsertionMarkerManager {
     insertionMarker.queueRender();
     renderManagement.triggerQueuedRenders();
 
-    // Position so that the existing block doesn't move.
-    insertionMarker.positionNearConnection(imConn, closest);
     // Connect() also renders the insertion marker.
     imConn.connect(closest);
 
-    let originalOffsetInBlock = imConn.getOffsetInBlock().clone();
+    const originalOffsetToTarget = {x: closest.x - imConn.x, y: closest.y - imConn.y}
+    const originalOffsetInBlock = imConn.getOffsetInBlock().clone();
     const imConnConst = imConn;
     renderManagement.finishQueuedRenders().then(() => {
+      // Position so that the existing block doesn't move.
+      insertionMarker?.positionNearConnection(imConnConst, originalOffsetToTarget, originalOffsetInBlock);
       insertionMarker?.getSvgRoot().setAttribute('visibility', 'visible');
-      insertionMarker?.repositionAfterConnectionResize(imConnConst, originalOffsetInBlock);
     });
 
     this.markerConnection = imConn;