Comment 0 for bug 238733

Under Windows (and Wine), a right-click occurs on ButtonRelease.
Under Gnome, a right-click occurs on ButtonPress.
Furthermore, the subsequent Release acts like a left-click.

Here are several consequences:

a) I the mouse slips towards a context menu between Press and Release, an unwanted menu entry is executed.
Windows is a less surprising platform to practice mouse skill.

b) If a context menu is misplaced due to program error, the result is the same without slipping.
For example, this is presently the case of Firefox and Thunderbird.
If a right-click is made too close to the window's right border for a left corner of the menu to appear at the cursor, the menu will appear flush to the window's right border with the top or bottom edge aligned on the cursor. But the menu is too low, so that when the cursor is near the window's bottom, it is inside the menu.
In consequence, right-clicking in that bottom right area has the following consequences :
- Firefox switches page direction,
- Thunderbird deletes the message you're reading (bug #107819)
These FF/TB bugs are not bugs under Windows.

c) There are probably more subtle consequences.
Ubuntu bug #187313 might well not be a bug if right-click occurred on ButtonRelease.

Additionally, it seems to me that L/R-click on ButtonRelease leads to simpler and hence stronger logic.
To determine if a click is long, it seems easier to measure the time between Press and Release when Release occurs than to start a timer when Press occurs and wait until it times out and gets a long click or is aborted by Release and gets a short click that occurs on ButtonRelease anyway.
I leave the multiple clicks case difference as an exercise.

Although different usage implies different problems, what is true for right clicks is true for left clicks.