DrRacket GUI for plai/gc2/mutator crashes

DrRacket GUI that displays the heap for plai/gc2/mutator language seems to run out of memory when the heap has sufficiently large number of floats, but the mutator program itself doesn't stop executing and causes DrRacket to display a ton of out of memory window.

An example mutator that causes this error is shown below.

#lang plai/gc2/mutator

(allocator-setup "mark-and-sweep.rkt" 500) ; This is a standard mark-and-sweep gc collector as described in https://www.eecs.northwestern.edu/~robby/courses/321-2015-winter/lecture12.pdf

(define guess 0)

(define (sqrt x) ; dumb way
  (set! guess x)
  (sqrt-rec (/ x 2) x))

(define (sqrt-rec guess x)
  (if (close? guess x)
      guess
      (begin
        (set! guess (improve guess x))
        (sqrt-rec guess x))))

(define (average x y)
  (/ (+ x y) 2))

(define (square x)
  (* x x))

(define (abs x)
  (if (< x 0)
      (- 0 x)
      x))

(define (improve guess x)
  (average guess (/ x guess)))

(define (close? guess x)
  (< (abs (- (square guess) x)) 0.001))

(define (run num)
  (if (= 0 num)
      0
      (begin (sqrt 1000000)
             (run (- num 1)))))

(define a (run 100))

Closing the heap window doesn't cause DrRacket to crash, so the problem seems to be with the rendering of heap window.

Start by reproducing the supplied #lang plai/gc2/mutator example with the mark-and-sweep collector and a heap size of 500, then inspect the heap window rendering path. Done means the heap display no longer exhausts memory or produces repeated out-of-memory dialogs while the mutator continues running.