Chrome Version       : 57.0.2987.123
OS Version: 9202.56.1
URLs (if applicable) : https://mail.google.com/mail/u/0/#inbox?compose=new
Other browsers tested:
  Add OK or FAIL after other browsers where you have tested this issue:
     Safari 5: N/A
  Firefox 4.x: N/A
     IE 7/8/9: N/A

What steps will reproduce the problem?
1. Add at least 2 input languages to Chrome OS. https://support.google.com/chromebook/answer/1059492 has info on how to add additional keyboards. (My Chormebook is configured to input English and Tamil.)
2. Open the Gmail app *in a window*. The app can be installed from https://chrome.google.com/webstore/detail/gmail/pjkljhegncpnkpknbcohdijeoejaedia. Make sure to open the app in its own window.
3. In the Gmail app window, click on the 'Compose' button.
4. Click on the input area for new email's body. Press Ctrl+Shift+Space to change input language.

What is the expected result?
Keyboard language changes.

What happens instead of that?
Keyboard language does not change. The issue goes away when opening Gmail in a tab, however. The issue seems to be present only on app windows.

Please provide any additional information below. Attach a screenshot if
possible.

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