I'm having problems with formulas in release 1.4.4. To demonstrate one of the typical problems, I would like to describe an example that can be easily recreated.
Let's take an Excel spreadsheet with two sheets: "Sheet1" and "Sheet2". Enter two numbers in C1 and D1 cells on Sheet2. Then on "Sheet1" enter something like =Sheet2!C1 or =Sum(Sheet2!C1:Sheet2!D1) in one of the cells. Then open the Excel file using the Excel.Web control and save the document. Right after the save is complete, you should get an error message saying something like "Index was out of range.." at loading the Excel file. When you open the file in Excel, you will see #NAME? in the cell where you entered =Sheet2!C1 or =Sum(Sheet2!C1:Sheet2!D1) . When looking at the code of the cell, it can be easily seen that it now shows "='Sheet2!C1'()". So basically the web control added single quotes and parentheses to the original formula. I noticed that the web control always adds single quotes to the worksheet names, which makes the corresponding formulas invalid.
I would appreciate if you could look into this issue.