I can confirm the first issue.
But, if there's no space between "while" and "(", then it has no error tips.
For the second issue, in my Chinese system Windows XP, ctrl + space will do a input method switch, so, I cant reproduce it. Continuing enter "retu" will give the right tip "return".
Edit
After change the short cut to "ALT +/", I can't reproduce the second issue. It can give the correct tip list with the prefix I entered.
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