"activate instruments" in Play mode

It seems to me “activate instruments” in Play mode doesn’t change anything! What its purpose, please?
On page 563 of Manual:

When I deactivate it, the plugin still plays the instruments!

There’s a bug with this that’s been discussed in the last couple of days, here.

Are you actually deactivating it, or are you switching to Play mode and seeing that it appears to be turned off? From it’s “off” state, try clicking it twice. Now it should actually be off.

It is also the case in Dorico 3.5 that if you deactivate a VST instrument in Play mode and then save and reopen the project, that choice is not correctly saved and restored. That is a problem that we have fixed in our internal development builds ahead of the next major version of Dorico.

@dspreadbury do you mean Dorico 4?

@pianoleo I switch to Play mode to make sure they are activated and press activate instrument. For some reason, they get deactivated by themselves ( not sure how).

As explained in the thread I linked to above, when you switch to Play mode from Engrave or Print mode, the lights go out. That doesn’t mean that those plugins are actually inactive. In order to ensure that they are actually inactive, you need to turn them on then off again.

This has already been acknowledged as a bug.

I pressed it to activate the instrument and Dorico became unresponsive again and I had to force quit it! Here is the crash file. I have removed the SIR.vst3 ( the troubling reverb plugin ) when I loaded it.

Dorico Diagnostics.zip (2.1 MB)