Yup. We’ve discussed this here in this category for many years as the IE browser emulation registry setting was incrementally changed from 9 on up (SU2015 and later.) At one release it had to be increased to IEv10 because the Google Maps API wouldn’t support anything earlier.
Many of us especially ThomThom have been preaching for years not to rely upon the default setting, but to instead always include a <!DOCTYPE html> tag …
MSDN: How to Enable Standards Support
The HTML5 document type directive tells a webbrowser to display webpages in standards mode. … If your webpage uses one or more features that require standards mode and you do not include a standards-compliant !DOCTYPE directive , the resulting behavior depends on the version of Internet Explorer used to view the webpage.
… along with the meta tag …
That was back in 2016. Again, in later SketchUp releases it had to be set to emulate MSIE 10 minimum so that the Add Location would work. But likely SketchUp 2018 set the IE emulation up to 11 (0x2AF8), as that is what mine is set as.
And also ThomThom explained why SketchUp 2017 was still using UI::WebDialog for the embedded web services (EW, 3DW, Generate Report and Add Location) …
I did publish a set of reg files to set the emulation for testing or if it really becomes necessary (ie, such as after having to rerun an older installer to repair an older version SketchUp.)
Also for years the UI::Webdialog section, of the IDEAS page, of the pinned Ruby Learning Resources, has promoted ThomThom’s “Lost Manual” as well as the MSDN pages on HTML document compatibility.