extjs combo not defined error

I have a Panel. Inisde the Panel, I do a initComponent: function() {this.someCombo = new someDefaultCombo(...)} Then I do:

this.somePredefinedForm.items.add(someCombo); //Line 2

And I get:

Erro开发者_高级运维r: someCombo is not defined

at Line2.

But I am defining it at the top. So why there is js error?

EDIT: When I changed this to:this.somePredefinedForm.items.add(this.someCombo); , the error went away. But why?

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this.someCombo is te way to access someCombo. This is the object in Panel not something global like you try at the begining

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if you are executing this:

this.somePredefinedForm.items.add(this.someCombo);

not in initComponent function then make sure that this refers to object that contains initComponent function.