Design/Usage of Conditional Watchpoints

I'm trying to make use of conditional watchpoints for debugging my Java code.
In the snippet below, I created a watchpoint on
- EvalJavaConditionWatchpoint.str1
- EvalJavaConditionWatchpoint.NestedClass.str2

If I add a conditional expression for str2, auto-completion encourages me to enter something like
- System.out.println(this.str2)
but then fails on running with
- Conditional breakpoint has compilation error: str2 cannot be resolved or is not a field

If debug the app by having
- System.out.println(this)
for both fields as conditionals, I get

EvalJavaConditionWatchpoint@4cdf35a9
EvalJavaConditionWatchpoint$CallNestedClass@5eb5c224
EvalJavaConditionWatchpoint$CallNestedClass@53e25b76

So it seems the this variable is referencing to the caller instead of the referenced instance where the watchpoint is active.
I suppose this is a bug as also auto-completion proposes a different use of the this variable.
I was also also looking for some documentation about this feature, but was not able to find such - where could I find it?

Thanks,
Thomas

```
public class EvalJavaConditionWatchpoint {

public static void main(String[] args) {
new EvalJavaConditionWatchpoint().run();
}

void run() {
str1 = "abc";

new CallNestedClass().run();
new CallNestedClass().run();
}

String str1;

static class CallNestedClass {
void run() {
NestedClass nc = new NestedClass();
nc.str2 = "abc";
}
}

static class NestedClass {
String str2;
}
}
```