Close a widget but the associate '<div class="output_area">' still exists

Since 7.0 widgets in notebook are rendered in <div class="output_area">, but when I close a widget, the associate <div class="output_area"> still exists.

from ipywidgets import Layout, Button, Box
from IPython.display import display
items = [Button(description='example') ]
box1 = Box(children=items)
box2 = Box(children=items)
box3= Box(children=items)
display(box1)
display(box2)
display(box3)
box2.close()

output:

How could I remove this part ?

[dovahcrow]

Are we gonna solve this issue in ipywidgets or jupyter? As of today (ipywidgets 7.5.0, jupyterlab 1.0.1, this empty div problem is still there.

[nanoant]

FYI I identified the source of the problem in JupyterLab – each removed output is nested in some two additional divs:

<div class="p-Widget p-Panel jp-OutputArea-child">
  <div class="p-Widget jp-OutputPrompt jp-OutputArea-prompt"></div>
  <div class="p-Widget p-Panel jp-OutputArea-output p-mod-hidden"></div>
</div>

While 2nd inner div with p-mod-hidden gets display: none CSS the first jp-OutputPrompt jp-OutputArea-prompt has non-zero padding and border, even when has no content at all, causing the space to grow. I believe this is a problem at the junction of ipywidgets and JupyterLab. I don’t know if there is a way to remove output completely (instead hiding it), so these divs do not remain at all. My current workaround is an additional CSS:

.p-Widget.jp-OutputPrompt.jp-OutputArea-prompt:empty {
  padding: 0;
  border: 0;
}

This is far from perfect as still the internal DOM grows with empty divs, we just don’t see that anymore. And btw. please re-open this issue as the problem is NOT fixed.