how properties work vigilant oriented matlab?

i am perplexing emanate matlab category member non-static that's being updated outcome slight invocation, nonetheless i try change ability within category (apperently, i supposed matlab's memory management) creates duplicate vigilant following modifies it, withdrawal uncanny object's ability untouched.

classdef testprop  
    properties  
        numrequests=0;  
    finish  
    methods  
        duty request(this, val)  
            disp(val);  
            this.numrequests=this.numrequests+1;  
        finish  
    finish  
end  

.

>> a=testprop;
>> a.request(9);
>> a.request(5);  
>> a.numrequests  

ans = 0