[Lazarus] I cannot use System.Length() to calculate visible width of string, now !

["Андрей Гусев (Andrey Gusev)"]

Felipe Monteiro de Carvalho пишет:
>> Solution is clean: i must use check ifdef'ed WindowsUnicodeSupport to
>> choice between UTF8Length()/Length(). But maybe it already
>> implemented as universal and conventional solution.
>>     
>
> Why do you want to support disabled WindowsUnicodeSupport?
>
>   
Caption strings in some forms of my project must be defined dynamically.
Unit code, responsible to these strings definition and visible elemsnts 
dosposal, is universal and low-level.
I wouldn't like make assumtions  about  strings encoding in that  code.
That is my problem.
Have Lasarus way to solve it ?