Protected sheet - how to correct text in unlocked cells

[lisaopar]

The text disappears when I want to correct it (protected sheet).
Please see the discription of the problem in the attachment with figures.
Thanks for helping!

[adyteo]

I am not sure I understand what you would like to do. Do you want the text to disappear or not? Is there a data validation for the cell (text length?)?

[lisaopar]

Sorry if my question was not entirely clear!
If I double-click in a unlocked textcell, in a protected spreadsheet the text disappears!
Example:
If the cell contains the text: "Thursday is time to update"
I want to change to: "Friday is time to update"

If I double-click in this cell, all the text disappears and I have to type it again.
I do NOT want the text to disappear, but just change "Thursday" to "Friday".

The reason is that the cell is unlocked in protected sheet.
How can I get around this problem?

I am very grateful for an answer!

[adyteo]

Can you please check whether there is a macro in the excel file? The original text should not be deleted when you edit it. If there is a code behind the sheet, that may be the cause.