Using Oxygen and DevStyle Darkest Dark theme on Windows 10.
Open editor on a file that just fits into the editor vertically so no vertical scrollbar is needed. Scrollbar doesn’t appear. Extend a line so that it is longer than the visible window. Now use Alt+Shift+Y to toggle word-wrap. Note that some of the file is no longer visible as visible lines shift down. A vertical scrollbar should appear to allow scrollbar navigation to the parts of the file shifted off the editor view but no scrollbar appears.
This was replicated with a simple text editor on a TS file. The scrollbar does appear when the eclipse Classic theme is used.