PyQtgraph windows are automatically closed if no reference is kept to the plot

[jenshnielsen]

some like

for i in range(5):
    loop = qc.Loop(dac.ch1.sweep(0, 10, 0.5), delay=0.1).each(dmm.voltage)
    data = loop.get_data_set(name='testsweep')
    plot_1d = qc.QtPlot()  # create a plot
    plot_1d.add(data.dmm_voltage)  # add a graph to the plot
    _ = loop.with_bg_task(plot_1d.update, plot_1d.save).run()  # run the loop

results in all but the latest figure getting closed
but

plots = []
for i in range(5):
    loop = qc.Loop(dac.ch1.sweep(0, 10, 0.5), delay=0.1).each(dmm.voltage)
    data = loop.get_data_set(name='testsweep')
    plot_1d = qc.QtPlot()  # create a plot
    plot_1d.add(data.dmm_voltage)  # add a graph to the plot
    plots.append(plot_1d)
    _ = loop.with_bg_task(plot_1d.update, plot_1d.save).run()  # run the loop

all figures will remain open as a reference is kept to all of them.