[GH #1853] Dropdown is hidden when it is not in viewport

If the cell type is Dropdown or Handsontable, the dropdown component disappears when it is scrolled outside of the viewport and will not appear again.

Steps to reproduce:

  1. Open any dropdown cell
  2. Scroll down until the dropdown is not shown
  3. Scroll up again and the dropdown is not shown (cell is still in edit mode)

Demo:

Hi @hjeong1200

Thank you for contacting us. This is issue is most likely connected to the other one related to the dropdown visibility bug. We have it reported internally, so I will update you once we investigate it further and estimate.