In Atlantis, there are two text entry modes:
To switch back and forth between the Insert and Overwrite modes, press the Ins key.
Information about the current text entry mode is reported throught the corresponding section of the status bar.
When there is selected text in the document, typing automatically replaces the selection.
Atlantis also supports a multiple overtype mode allowing to overtype multiple selected fragments simultaneously. If you make a multiple selection, as shown on the illustration below:
and start typing, the new text (in our case "Mars") would replace each of the items of the multiple selection:
The multiple overtype mode is especially useful for populating table cells. If you select multiple table cells, like shown below:
and start typing, the new text (in our case, "100%") would be automatically inserted to each of the selected cells:
To terminate the multiple overtype mode, click anywhere in the document or press Esc.