I am trying to write a block diagonal matrix in LyX which clearly shows the blocks by separating them using vertical and horizontal lines. I found that I can use \cline{i-j} to draw a horizontal line between columns i and j. Similarly, I found that I can use \multicolumn{1}{c|}{#1} to write an element in the matrix which has a vertical line to its right.

I tried to create a math macro for the \multiline command because the first two arguments are always the same in my matrix. I did it as follows,

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However, when I close the file and reopen it, the macro changes to this

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I do not understand why this happens. I have used macros before and they never changed like this. Is there any problem in defining a macro for \multicolumn?

closed as off-topic by Torbjørn T., Martin Schröder, TeXnician, user31729, clemens Apr 21 '17 at 12:49

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If this question can be reworded to fit the rules in the help center, please edit the question.

  • Since this is a TeX-LaTeX site, I'd rather report such (obvious) bugs at lyx.org/trac/wiki/BugTrackerHome or LyX user/developer newsgroups. – PhilipPirrip Apr 16 '17 at 16:31
  • This is going to be fixed in the upcoming LyX 2.3 and 2.2.3 (see lyx.org/trac/ticket/10466). For now you can replace \multicolumn with \csname multicolumn\endcsname and it will be preserved on loading. As said, this is not really a question for tex.se. – G.M. Apr 18 '17 at 12:32
  • 4
    I'm voting to close this question as off-topic because it is about a bug in LyX that has been reported at the appropriate place (lyx.org/trac/ticket/10466) and will be fixed in an upcoming version. – Torbjørn T. Apr 21 '17 at 12:17

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