can't see temporary table on list/ in hirearchical structure to the left

CREATE TEMPORARY TABLE SplitValues (
splitted VARCHAR(1000) NOT NULL
) ENGINE=MyISAM;

The table is there coz I can select from it, it is just not visible in hirearchical structure (refresh does not help).

Should that be visible or not ?

same thing: tools/export database as sql

The table is not on list, but I would like to export it.

Does it show up when you fire SHOW TABLE STATUS?

No.

There you have the reason. If temporary tables are excluded in SHOW TABLE STATUS, then HeidiSQL does not show them.