[p5.js 2.0 Bug Report]: mouseIsPressed stays true after losing focus, no blur reset for mouse state

[avinxshKD]

Most appropriate sub-area of p5.js?

• Accessibility
• Color
• Core/Environment/Rendering
• Data
• DOM
• Events
• Image
• IO
• Math
• Typography
• Utilities
• WebGL
• Build process
• Unit testing
• Internationalization
• Friendly errors
• Other (specify if possible)

p5.js version

No response

Web browser and version

No response

Operating system

No response

Steps to reproduce this

Hold a mouse button on the canvas, alt-tab away, release the button, come back. mouseIsPressed is still true.

keyboard.js at least has _onblur (incomplete, see #8540). mouse.js has nothing, no blur handler at all. So mouseIsPressed and mouseButton just stay frozen at whatever they were when the window lost focus.

function draw() {
  background(220);
  text('mouseIsPressed: ' + mouseIsPressed, 20, 50);
}

Steps: hold mouse on canvas → alt-tab → release → come back → still shows true

Fix would be the same pattern as the keyboard blur fix, add an _onblur to mouse.js that resets mouseIsPressed = false.

[avinxshKD]

hey @ksen0 same pattern as #8540, that one's keyIsPressed staying stuck after blur, this is mouseIsPressed doing the same. keyboard.js at least has _onblur (even if it's incomplete), mouse.js has nothing at all.

happy to put up a PR for 2.x if this makes sense

[avinxshKD]

Hey @apoorvdarshan I am working on it and was waiting for @ksen to assign me, thanks

[apoorvdarshan]

Hey @ksen0 @avinxshKD — apologies, I should have followed the contributing guidelines and claimed the issue before submitting the PR. Closing #8554 now. Will make sure to wait for assignment first going forward. Sorry about that!

[ksen0]

Thanks again for your patience @apoorvdarshan @avinxshKD !

@avinxshKD please feel free to go ahead with work on this one on 2.0. As you said it's similar to the key one in the other issue. I think only one of these should be done initially to get some feedback.

Why I'm a bit cautious: Although the tabbing-away behavior is not intuitive and buggy, its also not a regression (if I understood it well), so I want to be sure that changing the existing behavior doesn't have surprising side-effects. (Eg, in more complex uses, like in P5Live, which might rely on current behavior being stable - this is just a guess, I am not sure if there are side effects) I hope this clarifies why I think it's worth being a bit cautious about this one.

That said, as you write, mouse has no blur handler at all right now, so I think this is a better place to start.