2. How does this really work?

In XMLmind XML Editor, a formula is stored as the xxe-formula processing instruction. A processing instruction such as xxe-formula is allowed by the XML standard. Such processing instructions will be ignored by all XML software except XMLmind XML Editor.

Unlike in ``real'' spreadsheet software:

In a styled view, a formula is rendered using a special purpose gadget, which is at the same time an indicator and a button. Its color gives you a hint about the state of the formula.

IconDescription
Unknown state. Formulas contained in document modules included in the document being edited are ignored by the spreadsheet engine.
Parse error. Should not happen if you use the Formula Editor.
Evaluation error.
OK.

Disabled.

Disabling a formula means passivating it. That is, it is no longer used to update the document. In some cases, this is a handy alternative to removing it.

When the user hovers the cursor over one of the above icon without clicking it, a tooltip (also called ``balloon help'') is displayed. If the formula cannot be parsed (red icon) or evaluated (orange icon), the tooltip contains the corresponding error message. If the formula is working, the tooltip contains the last statement of the formula (a formula can contain several statements, see The language used to write formulas).

Clicking on the icon triggers special actions:

Double click

Open the Formula Editor to edit the formula.

Click with middle button

Disable (gray icon) or enable (green icon) the formula.