For the first time I'm using the RowColumn widget. In a first step I get
what I want : 10 columns and 15 lines of text fields.
The resource XmNpacking is set to XmPACK_COLUMN

In the Motif Programming Manual (p267), it si said : XmPACK_COLUMN specifies
that each of the celles should be the same size ... The value of
XmPACK_TIGHT allow each widget to keep its specified size ... Indeed my
columns should be of different sizes.
When the resource XmNpacking is set to XmPACK_TIGHT, I get only one column
with 10*15 lines.

Why this behavior ?

Thanks for your help