- actually use the signal compressor to prevent excessive updating,
  so emit the signals in the slot for timeout()
- slotLockSelector() was just an obfuscated m_d->allowUpdates = false;
  set it explicitly to make it consistent with the rest and remove this slot
- make sure currentColor is in the proper color space after lockUsedColorSpace(),
  otherwise our input widgets will switch right back when the dialog gets shown
- fix logic on which update calls to accept/ignore