The problem has been there for months… While using Mac, for global heroes like Falstad and Brightwing (not sure about Dehaka since I don’t play him), I cannot ping the cooldown of my z, which is really annoying since I really do need to show my teammates so that they can adjust the plan.
The user here also said they don’t see a tooltip pop up when they hover over it with the mouse cursor. Specific machine or in general? Can you at least cast the ability (mount on other heroes) with your mouse alone by completely avoiding the keyboard button?
I’ve had a similar problem in WOW where I couldn’t interact with linked items or keybinds on a part of my screen using the mouse. It had something to do with an invisible overlay that was put over the main window without my knowledge. After a lot of frustration, it turned out to be an addon, but some other users say this can also happen with graphics card and communications drivers and software such as the popular Discord.
Check your task manager (or whatever it is called in iOS) and see what else is running in the background and work from there. Disable non-essential processes until you figure out what it might be.