Extension|Author (truncated)|Version
---|---|---
vscode-eslint|dba|1.3.2
block-travel|sas|0.0.2
selectline-statusbar|tom|0.0.2
Reproduces without extensions: Yes
Currently there are two ways to change font size: by zooming the UI with keyboard shortcuts or menu options and by ctrl+scrolling with "editor.mouseWheelZoom": true . But it is impossible to reset the zoom level after zooming with mouse wheel except by restarting the editor.
The issue stems from this: ctrl+scrolling changes the font size independent from the UI zoom level, and "Zoom In/Zoom Out/Reset Zoom" actions change the UI zoom level (which affects visible font size) but not the font size set by the former.
Here's a recording of me (using a fresh VS Code Insiders 1.17.0 build) ctrl+scrolling (zooming out) then changing the UI zoom level then ctrl+scrolling again (zooming in). You can see that the changes to font size are impossible to reset, they don't even register in the settings file.

Another bug report with the same issue: #25047 (closed because of a vague description).
+1
A workaround is to just reload the window :s .
In VSCode 1.33 (March 2019), there's a command called Editor Font Zoom Reset that does exactly what is requested here (I believe). It has been implemented in https://github.com/Microsoft/vscode/issues/48838 which shipped as part of May 2018 release so maybe it just flew under the radar?
Anyway, I came to this issue because I also thought that there's no way to reset font zoom, only later discovered that there is.
Zooming with mouse wheel doesn't update the configuration window.zoomLevel and there is no editor.fontZoomLevel configuration so if there is anything that depends on it, it won't work properly.
Like if you have a TextEditorDecoration that depends on the fontSize, lineHeight or zoomLevel, it won't behave correctly because none of this options will be updated when zooming through ctrl+mouse wheel.
I think the issue is that the mouse wheel zoom is changing the zoom level directly on the Browser and is not changing the configuration or firing any configuration change event.
I also had this issue, resolved by reloading the window, but I didn't expect "scroll wheel zoom" at all (using two fingers to scroll on a trackpad, apparently somehow I accidentally zoomed instead). I've disabled scroll wheel zoom, but having an option to reset the editor zoom in the same part of the GUI as the other zoom options would be nice (that's where I would have expected to find it)
Most helpful comment
In VSCode 1.33 (March 2019), there's a command called Editor Font Zoom Reset that does exactly what is requested here (I believe). It has been implemented in https://github.com/Microsoft/vscode/issues/48838 which shipped as part of May 2018 release so maybe it just flew under the radar?
Anyway, I came to this issue because I also thought that there's no way to reset font zoom, only later discovered that there is.