When ticking the Show Item Codes, the Item listboxes shows the item code in front of the item name.

/Joe

If i put this value on 5, I expect that when I create a new workorder it should give as date, today + 5 days.

No matter what I do, the new work order entry screen only shows me todays date.
I have also checked it on your FA demo but the same issue.

Is my expectation wrong, or is it something else?

And i'also trying to find out the working of another option:

Show Item Codes (which can be found in preferences under Miscellaneous)

Setup --> Display Setup --> Show GL Information:
This item can be ticked on or off, but what does it do / change

The link to GL information doesn't  show up in AR/AP transactions.

Look in the Forum Announcement for answer to this. You shoul probably be an accountant to understand this.

Past Due Days Interval: In the customer/Supplier aging analysis there is a time-span between the due amounts. This is the time-span in days.
Accumlate batch shipping: If you are accumulating several delivies into one invoice, you can choose to accumulate the shipping cost from each delivery. Otherwise only a single shipping cost is debited.
Dimension required by after: The dimension will default be set as a closing date after these days. Can be overridden when creating.
Work Order Required By after: The work order will be set as required by this day. Can be overridden when creating.

/Joe

Setup --> Display Setup --> Show GL Information:
This item can be ticked on or off, but what does it do / change

Banking and General Ledger --> Journal entry --> Reverse transacion:
This item can be ticked on or off, but what does it do / change

Setup --> Show GL Information -->
Past Due Days Interval:
Accumulate batch shipping:
Dimension Required By After: XX days
Work Order Required By After: XX days

and finally What do the above 4 items do or change.