How to reproduce

• connect to front-office
• click on an rich text area where there is a front-office edition
• click on the button to insert a picture

Actual behavior

• a pop up is displayed to select a picture. The icon to close the pop-up is missing (square) and this is the log in the console of the browser :

  VM3588:36 GET http://cmsdev-intranet.customer.fr/intranet-d-clic/plugins/core-ui/resources/font/ametys/AmetysIcon.woff 
  getStyle @ VM3588:36
  isStyle @ VM3588:36
  getWidth @ VM3588:36
  onRender @ VM3588:187
  finishRender @ VM3588:62
  finishRenderItems @ VM3588:123
  finishRender @ VM3588:124
  finishRenderChildren @ VM3588:127
  afterRender @ VM3588:61
  finishRender @ VM3588:62
  finishRenderItems @ VM3588:123
  finishRender @ VM3588:124
  finishRenderChildren @ VM3588:127
  afterRender @ VM3588:61
  afterRender @ VM3588:160
  callParent @ VM3588:13
  (anonymous) @ VM3588:19
  finishRender @ VM3588:62
  render @ VM3588:62
  doAutoRender @ VM3588:62
  show @ VM3588:68
  open @ VM3588:434
  _insertLocalImage @ VM3588:454
  onclick @ VM3588:463
  i @ VM3588:352
  fire @ VM3588:354
  t @ VM3588:353
  e @ VM3588:329
  m @ VM3588:329
  /intranet-d-clic/plugins/extjs6/resources/classic/theme-triton/resources/font-awesome/fonts/fontawesome-webfont.woff?v=4.4.0:1 GET http://cmsdev-intranet.customer.fr/intranet-d-clic/plugins/extjs6/resources/cl…theme-triton/resources/font-awesome/fonts/fontawesome-webfont.woff?v=4.4.0 
  /intranet-d-clic/plugins/extjs6/resources/classic/theme-triton/resources/font-awesome/fonts/fontawesome-webfont.ttf?v=4.4.0:1 GET http://cmsdev-intranet.customer.fr/intranet-d-clic/plugins/extjs6/resources/cl…/theme-triton/resources/font-awesome/fonts/fontawesome-webfont.ttf?v=4.4.0