Build an extra modal stack (reduce to a single component and not a list)
for the modal above our rich text editor. It uses its own dialogs with a
fix and quiet large z-index (65535) and we cannot render again the text
component if one of its dialog is open. A redraw will discard it.

# Conflicts:
#	src/main/java/org/olat/modules/contacttracing/ui/_i18n/LocalStrings_de.properties