I tested this out here

I think the problem doesn't come from the frameless attribute, but rather from the text attribute, that gets used in a wrong way.

@Yurik started an RFC to tackle the problem : T148706

For graphs (see T147768#2773162) we revisited the text attributes to be such as this:

In T147768#2773162, @JGirault wrote:

• Extra information with text attributes
  • "caption" = specifies extra information about a graph, displayed below the graph, Later this text could be shown in the footer of a full screen dialog, similar as how Maps render in a full screen dialog.
  • "alt" = provides alternative information for a graph snapshot, if a user for some reason cannot view it.
    • If "alt" is not specified but "caption" is, the alternative text will be created automatically from "caption".
  • "title" = specifies extra information about a graph, displayed on hover when the graph is still static.
    • If "title" is not specified but "caption" is, the title text will be created automatically from "caption".
    • Deprecated in favor of "caption".

Graphs and Maps attributes should be consistent. Maps can have an additional text attribute for <maplink> only: the text displayed as the link.

Copy-pasting my comment in the RFC T148706

Moving off the sprint board - the Discovery team won't be able to finish this work at this time.