Meta - On bug proliferation

[Marco]

Disclaimer: I'm not complaining, I'm just curious

How comes that, sometimes, bugs arise after the introduction (or modification) of some unrelated code?
For example

Code: Select all

v15.10.0001 - 2015-05-05 15:25
    ! Catalog: Did not process middle clicks. Did not process any click when
      empty (since recently). Both fixed.

But there was no (mentioned) change of mouse clicks processing in the previous betas.
Is XY code so intertwined to cause such butterfly effect?

[bdeshi]

Maybe more of a domino effect.
These are possible suspects:

Code: Select all

v15.00.0518 - 2015-04-30 09:48
    ! Tree: Under certain conditions the Tree would trigger a MouseUp when the 
      MouseDown did not happen on the Tree. Fixed.

Code: Select all

v15.00.0521 - 2015-04-30 22:36
    ! Tree: A tree-related fix in v15.00.0518 went a bit over the top. Defixed.

[admin]

Bingo, that was it.