An alternative is to place the scrubber (red line) on the split, right-click the clip that is to be inserted, then PLACE ON SEQUENCE AT CURSOR.
In some versions of Videopad that choice is missing on the context menu. Click the PLACE button instead, for that option.
Another approach is to press the <alt> key as the clips are dragged.
In a future version of VP it's hinted that there will be a new option to drag without snapping.