MultiSelect Closes When Selecting the words in search box

[erkinyldz]

To replicate this;
Open the multiselect dropdown.
Type some letters into search box.
Then select this words with using the mouse left click & dragging (Not with ctrl+a)
If you happen to make mouse up event while cursor is outside the dropdown, multiselect closes.

While this might not be considered a bug, it is definitely a bad user experience.