When I try to create a hysteresis trigger I get the following error message: "An item key must be used in trigger expression"

I have traced down the problem and I found that in version 1.6.6 there is a new piece of code in include/triggers.inc.php starting from line 716:

if($arr[ZBX_EXPRESSION_MACRO_ID] && !isset($ZBX_TR_EXPR_ALLOWED_MACROS[$arr[ZBX_EXPRESSION_MACRO_ID]]) )

{ error('Unknown macro ['.$arr[ZBX_EXPRESSION_MACRO_ID].']'); return false; }

else if( !$arr[ZBX_EXPRESSION_MACRO_ID] )

{ ... }

// line 716:
else

{ error('An item key must be used in trigger expression'); return false; }

Since the first two "if" expression does not allow the usage of

{TRIGGER.VALUE}

macro it goes always to this "else" branch, that gives an error.

I think the first "if" expression should be splitted into two to like this to allow valid macros to be used and only deny the not allowed macros:

if($arr[ZBX_EXPRESSION_MACRO_ID]) {
if (!isset($ZBX_TR_EXPR_ALLOWED_MACROS[$arr[ZBX_EXPRESSION_MACRO_ID]]) )

{ error('Unknown macro ['.$arr[ZBX_EXPRESSION_MACRO_ID].']'); return false; }

}
else if( !$arr[ZBX_EXPRESSION_MACRO_ID] ) {
: