If you drag an icon out of the Documents widget, it will remove the icon from the section and notify the Other Side if they are using ESPC Legal platform.
If you did this by accident, or realise you do actually need to provide that specific document, fear not, you CAN get it back. At the top right hand corner of the documents widget you will see a small icon of a rubbish bin/trash can, if you click on this icon a list of the document icons you have removed will be there. To bring one back into the document widget you just need to click on the red ‘X’ to restore it to the document icon section.