tag issue

[Gianmaria Lari]

I don't understand the following behaviour:

\version "2.18.2"

\tagGroup #'(testOne testTwo)

music = {

  \tag #'testOne b 

  \tag #'testTwo b^"M "

}

\keepWithTag #'testOne {\music~\music}

\keepWithTag #'testTwo {\music~\music}

I would expect this would generate two pretty similar scores: the first 

b~b 

and the second 

b^M~b^M

(so both with a tie)

but instead it generates: 

b b    (no tie!!)

and 

b^M~b^M 

 Where is the error?

* *

I noticed that if i invert the tag order 

music = {

  \tag #'testTwo b^"M" 

  \tag #'testOne b 

}

now the output is:

b~b

and

b^M b^M (no tie!)

Any help?

Thank you, g.