Hello, While updating the French version of examples/beamer.lyx for master, I saw that due to the translation of the message, the columns and column label go far in the left margin and do not appear completely to the user in the "Colonne(s)" inset(s).
Changing the Margin to "Manual" in the "Column(s)" styles of the beamer layout solves this, patch attached.
-- Jean-Pierre
--- lib/layouts/beamer.layout.orig 2016-03-15 19:06:27.142729458 +0000 +++ lib/layouts/beamer.layout 2016-03-15 19:07:02.022954108 +0000 @@ -596,7 +596,7 @@ Style Column Category Columns - Margin Static + Margin Manual LatexType Command LatexName column ParSkip 0.5 @@ -624,7 +624,7 @@ Style Columns Category Columns KeepEmpty 1 - Margin Static + Margin Manual LatexType Environment NextNoIndent 0 ParIndent MM