message: Replace the `:unresolved` CSS rule. It is deprecated.
diff: @@ -48,9 +48,8 @@ EXTRATERM-MAINWEBUI {
  bottom: 0;
  }
  -*:unresolved {
  - background-color: red;
  - border: pxToRem(1px) dashed red;
  +*:not(:defined) {
  + display: none;
  }
  #ID_MENU_BUTTON {
  