In Tuleap version 9.10.99.64 on CentOS 6.9 with PHP 5.3.3
When I try to edit the Trove Categorization in project admin,
i see the list of root categories but i don't see the combobox to set category values.

The problem seems in
www/include/trove.php: 144
for ($i=1;$i<=$GLOBALS['TROVE_MAXPERROOT'];$i++) {

my PHP version don't resolve the global var $TROVE_MAXPERROOT in its defined value 3.

I'm not a PHP programmer but I've noticed that if I am substituting:
$TROVE_MAXPERROOT = 3;
with
global $TROVE_MAXPERROOT;
$TROVE_MAXPERROOT = 3;
in www/include/trove.php: 11
I see the combobox.

Otherwise I see the combobox if I change
require_once('trove.php');
in
require('trove.php');
in src/www/project/admin/group_trove.php: 25

Googling, I have read: "in PHP 5.3, variables must be declared global outside the function if you want to use it globally within the function." (link https://forum.joomla.org/viewtopic.php?t=498905).

Best Regards
Lucio