The headline says almost everything.
It would be very nice to have this condition. There is only a condition for “Mouse button is pressed” once.
Maybe there are ways to bypass this with “timer events” or “variable counts”. I have not test this options yet.
I think a simple double click should not be generated so cumbersomely. Therefore, I ask the feature request.
I think you could benefit from it in many game genres.
While I do agree that this would be nice, there is a problem:
Most android phones would not support it and the most popular browsers for android phones don’t support it as well. We can’t really ship a feature that only works in certain cases in the core events of GDevelop.
I understand if a feature doesn’t work on every supported device, then you don’t implent it.
BUT, what if it is clear from what device it is?
For example:
Condition “The mouse wheel is scrolling down/up” is for mouse only, right?
If dblclick event is the only event for mouse AND touch then it seems impossible. But maybe it is possible to separate. Or a function to simulate a double click?
These are just a few thoughts on my part. If it is not possible, then…
Well, “native” double click isn’t available at least. The native double click is nice, because the user can define the time between click from the OS settings, and it is consistent everywhere. We can make a “fake” double click by using a timer, but the timing might be uncomfortable for some users. If we go for the last option, it might be interesting to make it a user extension, as those can be modified by users as they are coded with events, allowing to tweak the double click if needed for an optimal user experience.
This seemed easy enough to do in an extension, so I made one real quick.
Here you go if you want to test it out before it’s reviewed fully: Double-Click Extension · Issue #95 · GDevelopApp/GDevelop-extensions · GitHub
Interesting.
I watched the “Add Function section” for the first time seriously. Seems to be a really powerful section by the way. I wondered how I could consider several buttons…and here it is. Thank you Silver-Streak.
I’ve tested it and it works for me. 
I literally started learning how to use gDevelop 11 days ago and I have one semester of programming. I put this in (and it worked!) in 2 minutes!
Thank you!
Generally I think if they could easily add a feature, they would have done so already.