I tried this simple action but it seems to have no effect.
Since it's a toggle I'd probably need to test if it is already on. Right now I'm just testing if variables were captured. If not, I thought I could turn this feature ON if it is off.
Edit:
I added an "If not marked" condition. The action seems to be accessing the menu but does not set it to "marked".
I can confirm this unexpected behavior. Here's my macro that is much the same as yours, except I have used the path of the menu item:
**Requires: KM 8.2.4+ macOS 10.11 (El Capitan)+**
(Macro was written & tested using KM 9.0+ on macOS 10.14.5 (Mojave))
#### DOWNLOAD Macro File:
<a class="attachment" href="/uploads/default/original/3X/3/2/325b8b290b6a186612f2d59d342cb89754307f7b.kmmacros">TEST Show Menu and Select Item.kmmacros</a>
**Note: This Macro was uploaded in a DISABLED state. You must enable before it can be triggered.**
---
<img src="/uploads/default/original/3X/5/a/5a20678d67233573ba9a2e943af39a4566a8cc5c.png" width="630" height="1035">
This does NOT check the `View>Developer>Allow JavaScript from Apple Events` menu item.
So, I thought maybe a more "manual" approach might be needed where the macro does a "type select" of the menu item. So I modified my macro to do just that:
### MACRO: TEST 2 Show Menu with Type Select
~~~ VER: 1.0 2019-12-04 ~~~
**Requires: KM 8.2.4+ macOS 10.11 (El Capitan)+**
(Macro was written & tested using KM 9.0+ on macOS 10.14.5 (Mojave))
#### DOWNLOAD Macro File:
<a class="attachment" href="/uploads/default/original/3X/d/7/d763e7bf6ba0e6cc5e86dcad2ef5d5b7ea81544a.kmmacros">TEST 2 Show Menu with Type Select.kmmacros</a>
**Note: This Macro was uploaded in a DISABLED state. You must enable before it can be triggered.**
---
<img src="/uploads/default/original/3X/3/5/35b33d565fbda7e842f627fdc80f9feab0ffa9f5.png" width="630" height="1356">
This macro also FAILS to check the target menu item.
@peternlewis, I believe this may be a bug, either with KM or with Chrome.As an addition test, I tried this action:
It worked as expected.
So, I think it makes it more likely that the bug is with Chrome.
It doesn't look like a bug, it looks like a (moderately sensible) deliberate choice.
If you can change that menu selection via AppleScript, then the menu is a waste of time as far as security goes (which it probably is anyway, but that ship has sailed).
I expect they explicitly blocked changing that menu.
Even more impressive, you cannot use simulated Type-Ahead to select the menu, so they seem to have done a fairly good job at blocking automated control of the menu selection (of course, that probably also means they have blocked accessibility control).
Thank you, gentlemen, for looking at this. It DID cross my mind being able to set this with a script could be a security loophole. 
@JMichaelTX, thanks for showing how to reuse the Macro Title and write the menu path directly. Both very helpful.
It even blocks the use of screen sharing to select it! No effect at all!
I’d thought there was something wrong with my browser or the OS — but as soon as I walked over to the physical computer and used its own trackpad to select “Allow JavaScript from Apple Events,” it worked fine.