struct Foo
{
    int foo;
};

int main()
{
    Foo foo1;
    Foo foo2;
    Foo foo3;
    Foo foo4;
    return 0; // Break here
}

• Expand and collapse foo3.
• Right-click L&E -> Toggle any option (Use Debugging Helpers, Sort Members etc.)
• foo3 is no longer expandable...

The same behavior is observed with 3.4 (didn't test with earlier versions), except Sort Members, which causes the entire L&E to be cleared.