Width of
left and
right block/column is usualy set in the style.css document of a XOOPS theme as seen below:
For left column/block
td#leftcolumn {width: 180px;font-size:12px;}
For right column/block
td#rightcolumn {width: 180px;font-size:12px;}
The codes above are self-explanatory and by modifying the width value your block/column will get wider/shrink according to the entered value