Bug in getVectorFieldImage() in ExportRender2D

[nik-liegroup]

I think this produces wrong values for "start" and "end", resulting in only one z-slice being displayed, no matter which z_range:
z_range = [0, 5, 10, 1000][params["stack"]["z_proj"]]
start = np.clip(params["stack"]["z"] - z_range, 0, stack.shape[2])
end = np.clip(params["stack"]["z"] + z_range, 0, stack.shape[2])

Setting im = stack[:, :, :, 0:11] manually fixed the problem for my stack.