# Edit source

## With Orbeon Forms 2017.2 and newer

The "Edit Source" button under the "Advanced" tab in the toolbox opens the "Edit Source" dialog.

![](https://4129616727-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LEkBiSDvlXs3VWiO0Zu%2F-LFZt2gpdgtXSCCHe0-f%2F-LEkBvjyJnZXF5GahqjH%2Fadvanced-menu.png?generation=1529627341696626\&alt=media)

## With Orbeon Forms 2017.1 and earlier

The "Edit Source" icon in the top right corner of the form area opens the "Edit Source" dialog.

![Edit Source button](https://4129616727-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LEkBiSDvlXs3VWiO0Zu%2F-LEkBmMpnaxnftLGDglW%2F-LEkC9AcL_rUDZeFg89a%2Fedit-source-button.png?generation=1528743372228663\&alt=media)

## Functionality

This is an advanced feature and it must be used very carefully.

Form Builder uses XHTML+XForms as form definition representation. The format must be well-formed XML. The dialog shows a text editor containing that representation.

![Source editor](https://4129616727-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LEkBiSDvlXs3VWiO0Zu%2F-LEkBmMpnaxnftLGDglW%2F-LEkC9AfGRBJZuS6rZJf%2Fedit-source-editor.png?generation=1528743372420660\&alt=media)

It is possible to edit the XML representation in the dialog, or to copy/paste it to an external editor for further changes. After saving changes from the dialog, those are immediately taken into account by Form Builder.

*NOTE: You have to be cautious when doing so because it is possible to break the form by making changes! We recommend that you learn about XForms before making such changes.*