Bug summary

I was playing with@timhoffm's new example at#28546 and found that, with QtAgg, when I hit the "configure subplots" button the image subplots immediately move downwards.

Code for reproduction

importmatplotlib.pyplotaspltimportnumpyasnpfrommatplotlibimportcolorsnp.random.seed(19680801)datasets= [    (i+1)/10*np.random.rand(10,20)foriinrange(4)]fig,axs=plt.subplots(2,2)fig.suptitle('Multiple images')# create a single norm to be shared across all imagesnorm=colors.Normalize(vmin=np.max(datasets),vmax=np.min(datasets))images= []forax,datainzip(axs.flat,datasets):images.append(ax.imshow(data,norm=norm))fig.colorbar(images[0],ax=axs,orientation='horizontal',fraction=.1)plt.show()

Actual outcome

Initially I get the expected plot

but when I hit the "Configure subplots" button, without changing any subplot settings I have

Expected outcome

Subplots don't move until I tell them!

Additional information

I have reproduced this back to v3.6.3 with QtAgg (I haven't tested further back). I cannot reproduce with TkAgg.

Operating system

Ubuntu

Matplotlib Version

main, 3.8.4, 3.6.3

Matplotlib Backend

QtAgg

Python version

3.9.19, 3.12.3, 3.11.6

Jupyter version

N/A

Installation

conda