Firefox has a huge bug in Chinese input

Select the text in the text input box to type (overlay typing), the Chinese input method will flash, then nothing will be typed and the selected text will disappear. 在文本输入框中选中文字进行打字（覆盖打字），中文输入法会闪一下，然后什么也打不出来并且选中的文字也不见了。 As in the following figure, it almost always happens when you select and overwrite text. 就像下面图中情景一样，对文字进行选择覆盖的时候几乎一定会发生。