How to get a reference to MainComponent from within another Component in another window?

If you have a second Window, with its own Component, is there a way to get a reference to the MainComponent? Or should you store a reference to it during creation of the second Component? Or maybe I don’t know what I’m talking about… :wink: I’m thinking I want a button in the second Window to call a function in the MainComponent…

in each class, add a lambda argument to their constructors and store them as members.
In the class that spawns/owns both components, pass in appropriate lambdas.
Make whatever GUI element you want call that lambda when clicked.

struct Foo : Component //or DocumentWindow or TopLevelWindow or...
    Foo(std::function<void()> f) : func(std::move(f)) { }
    void mouseDown(const MouseEvent& ) override { if( func ) func(); }
    void memberFunc() { DBG( "this is a member func of Foo" ); }

    std::function<void()> func;

struct MyApplication : JUCEApplication
    std::unique_ptr<Foo> foo1, foo2;
    void initialise(const String& commandLine) override
        foo1 = std::make_unique<Foo>(nullptr);
        foo2 = std::make_unique<Foo>(nullptr);

        foo1->func = [this](){ foo2->memberFunc(); };
        foo2->func = [this](){ foo1->memberFunc(); }


Untested, but you get the idea…