ModalWindow dialog rendering issue

Reported by client:

In some situations, after copying a document, a blank screen appears instead of a screen with the folder structure and existing documents. You then have to scroll down to see the contents of the screen.

Detail / technical info:

Bloomreach has two methods to determine the height of a dialog (heightUnit); based on px or based on%. The px method is the default, but the% method is the cause of the bug. As mentioned, the px method is the default, but it is overwritten as soon as you open the dialog of the taxonomy picker, then the method becomes%. Then the heightUnit will never be reset to px again. In addition, this only happens if there are more than 27 (this is not an exact number) folders available in the left side of the dialog. Reloading the CMS sets the heightUnit back to px and is therefore the workaround.

Researched Bloomreach / Wicket code: org.apache.wicket.extensions.ajax.markup.html.modal.ModalWindow
org.apache.wicket.extensions.ajax.markup.html.modal.hippo-modal.js
org.hippoecm.frontend.dialog.DialogWindow

• Choose a document containing taxonomy picker & many entries
• Open the document and open the taxonomy picker, close the taxonomy picker
• Close the document by clicking "Done"
• Try to copy / move the document.
• The layout of the dialog is now strange.