I try to use the following module: https://github.com/aek/aek-odoo/tree/11.0/custom_styles and I get this error:

Error:
Uncaught TypeError: r.transformAction is not a function

https://frapolli-catering.twanda-hosting.ch/web/static/lib/ace/ace.odoo-custom.js:6640
Traceback:
TypeError: r.transformAction is not a function
    at b.insert (https://frapolli-catering.twanda-hosting.ch/web/static/lib/ace/ace.odoo-custom.js:6640:27)
    at Object.exec (https://frapolli-catering.twanda-hosting.ch/web/static/lib/ace/ace.odoo-custom.js:6241:15)
    at https://frapolli-catering.twanda-hosting.ch/web/static/lib/ace/ace.odoo-custom.js:5510:34
    at o.r._emit.r._dispatchEvent (https://frapolli-catering.twanda-hosting.ch/web/static/lib/ace/ace.odoo-custom.js:1747:46)
    at o.exec (https://frapolli-catering.twanda-hosting.ch/web/static/lib/ace/ace.odoo-custom.js:5529:45)
    at s.onTextInput (https://frapolli-catering.twanda-hosting.ch/web/static/lib/ace/ace.odoo-custom.js:2126:40)
    at b.onTextInput (https://frapolli-catering.twanda-hosting.ch/web/static/lib/ace/ace.odoo-custom.js:6674:29)
    at A (https://frapolli-catering.twanda-hosting.ch/web/static/lib/ace/ace.odoo-custom.js:1115:250)
    at HTMLTextAreaElement.O (https://frapolli-catering.twanda-hosting.ch/web/static/lib/ace/ace.odoo-custom.js:1120:21)

Any idea for troubleshooting this?

Thanks