Steps to reproduce

1. enter an incorrect formula, =sum(1
2. switch to another sheet

Actual result

• In firefox, zss pops up an error message then still switch to another sheet. Keep in editing mode.
• In IE9, zss doesn't pop up any error message and just switch the sheet. Still keep in editing mode.
• In Chrome, zss pops up an error message and doesn't switch the sheet in the original sheet. keep in editing mode.

Debug Information

In Excel, if you enter a formula that it cannot fix for you, it will pop up an error message and keep a user in edit mode until complete a valid formula.