Hi Murto,
The Archicad objects have a fairly complex set of macros that perform various task so it can be difficult to isolate the specific code for the opening symbol that you wish to replace with an arrow.
You have to open the object you want to edit and start searching.
Typically the object will reference an opening type (sliding window, swing door etc.) controlled by an integer (eg. sliding window = 1, swing door = 2 etc.). This integer/value will then be passed to a macro that returns the necessary response.
It would be best to enable the sliding type in the object that gives you the panel config you want, rather than trying to change the symbol. Graphisoft create there objects with very specific and sound logic, so if you start trying to "fudge" a part of them to get what you want you may find it causes inconsistencies; your "side hung" will be a side hung even if you change its symbol to sliding, which could cause inconsistencies.
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