To create or edit a Hidden order in Mosaic, click on "Advanced" in the Order Entry window. Click the "Iceberg --" field and choose "Hidden". Likewise, to remove the Hidden attribute simply click on "Advanced" followed by "Hidden" and hit the backspace or delete key on your keyboard.
You can also add the Hidden column to your "Orders" tab in the Mosaic Activity panel by clicking on the Configure (wrench) icon in the top right corner followed by "Settings." In the right-hand column click on the green plus sign next to "Order Attributes". Select "Hidden" and click Add. Click Apply to save your changes and OK to close the window.
Additional Information
- Hidden Orders page of the IBKR website.
- Hidden Orders Study Notes