volume bar thinks mouse is pressed if released outside area

[Shahbaz Youssefi]

Steps to reproduce:

- Open indicator-sound (click on volume icon)
- Press the mouse in volume slide (don't release)
- Move mouse to outside the slide widget (not on another button, or outside indicator-sound)
- Release the mouse
- Optional: click on the indicator-sound window where there is no button. Nothing happens, but you can click as much as you want. (Even if there is a button, the behavior is the same)
- Move mouse back to volume slide

Expected behavior: volume slider doesn't change with mouse motion

Observed behavior: volume slider follows mouse motion as if mouse is still pressed

---

I am reporting this bug here because particularly with indicator-sound, the volume slider is quite thin, so if you are not precise, you could release the mouse easily outside the area. What's more, sometimes you want to lower the volume because some music you don't want starts playing, so this could happen:

- Lower the volume with a focus on changing the music
- Moving fast, the mouse button release happens outside the slider area
- Change the music
- Move back to the slider with the intention of raising volume
- BAM, the slider still thinks the mouse is pressed, and the volume may potentially be raised to maximum depending on where your mouse is.

---

If I may suggest (based on guessing completely), the slider widget needs to check the state of the mouse button on mouse motion event.

ProblemType: Bug
DistroRelease: Ubuntu 14.10
Package: indicator-sound 12.10.2+14.10.20141010-0ubuntu1
ProcVersionSignature: Ubuntu 3.16.0-30.40-generic 3.16.7-ckt3
Uname: Linux 3.16.0-30-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.14.7-0ubuntu8.1
Architecture: amd64
CurrentDesktop: Unity
Date: Thu Feb 5 12:02:30 2015
SourcePackage: indicator-sound
UpgradeStatus: Upgraded to utopic on 2014-11-01 (95 days ago)

[Shahbaz Youssefi (shabbyx)]

Cannot reproduce in 17.04. Must be fixed already.