Function onMouseDown

samples/common/codehighlight/codemirror.js:7293–7328

(e)

  // middle-click-paste. Or it might be a click on something we should
  // not interfere with, such as a scrollbar or widget.
  function onMouseDown(e) {
    var cm = this, display = cm.display;
    if (signalDOMEvent(cm, e) || display.activeTouch && display.input.supportsTouch()) { return }
    display.input.ensurePolled();
    display.shift = e.shiftKey;

    if (eventInWidget(display, e)) {
      if (!webkit) {
        // Briefly turn off draggability, to allow widgets to do
        // normal dragging things.
        display.scroller.draggable = false;
        setTimeout(function () { return display.scroller.draggable = true; }, 100);
      }
      return
    }
    if (clickInGutter(cm, e)) { return }
    var pos = posFromMouse(cm, e), button = e_button(e), repeat = pos ? clickRepeat(pos, button) : "single";
    window.focus();

    // #3261: make sure, that we're not starting a second selection
    if (button == 1 && cm.state.selectingText)
      { cm.state.selectingText(e); }

    if (pos && handleMappedButton(cm, button, pos, repeat, e)) { return }

    if (button == 1) {
      if (pos) { leftButtonDown(cm, pos, repeat, e); }
      else if (e_target(e) == display.scroller) { e_preventDefault(e); }
    } else if (button == 2) {
      if (pos) { extendSelection(cm.doc, pos); }
      setTimeout(function () { return display.input.focus(); }, 20);
    } else if (button == 3) {
      if (captureRightClick) { cm.display.input.onContextMenu(e); }
      else { delayBlurEvent(cm); }
    }
  }

  function handleMappedButton(cm, button, pos, repeat, event) {
    var name = "Click";