The bugs my father reports to me usually sound impossible and it’s some incorrect assumption of his that’s causing the behaviour. But sometimes there are genuine bugs that leave me speechless “when I see it”.
Sheet names in Excel should not contain the following characters:
|[||U+005B||left square bracket|
|]||U+005D||right square bracket|
The current version (2013) prevents the user from typing them at all while in Rename mode.
This check seem to be implemented using the raw key codes (before they are translated by the OS).
On Windows 7 (64bit), when using the Bulgarian (Typewriter) keyboard layout, Excel prevents the user from entering characters that would be invalid if the English layout was used.
|б||U+0431||Cyrillic small letter be|
|М||U+041C||Cyrillic capital letter em|
|ч||U+0447||Cyrillic small letter che|
|ц||U+0431||Cyrillic small letter tse|
|Б||U+0411||Cyrillic capital letter be|
With the exception of the solidus, all other characters are otherwise valid and can be produced using the workaround below. The bug is rather annoying, since it prevents users from entering 5 letters (!). It probably affects other keyboard layouts as well.
05 December 2014