# Possible bug with Dataset formatting for incompatible shapes and Missing

Bug introduced in 11.0.0 and fixed in 11.1

A support case with the identification [CASE:3707497] was created.

[...] It does appear that Dataset typesetting in version 11 is not behaving properly, and I have forwarded an incident report to our developers with the information you provided. [...]

The problem:

{<|"a" -> Range[5]|>, <|"a" -> Missing["KeyAbsent", "a"]|>} // Dataset


More detailed example shows that 5 is the magic number and that it will be quite common for those who use KeyUnion:

 Table[<|ToString[i] -> Range[i]|>, {i, 2, 6}] // KeyUnion // Dataset


Keywords:

TypeSystemPackageScopeAtomShape[34]

• It worked in Version 10.4.1, but does not in Version 11.0.0. – gwr Sep 6 '16 at 11:05
• I note, that Missing["reason"] does not work in general (e.g. the reason is not printed anymore when the Datasetis displayed)? – gwr Sep 6 '16 at 11:24