in this case :
<div style="display: flex;flex-direction: 'column'; width: 800px; height: 600px">
<div style='width: 300px' id='leftside'></div>
<div style='flex:1'>
<Draggble bounds='parent'><div>bound drag</div></Draggble>
</div>
</div>

bound option seems work fine to lock the draggable div in 800*600 area, but offset left was ignore. i mean draggable div was not suppposed to be able to dragged to x=0px , is was supposed to 300px

is there anyone help me? thanks very much