Autocomplete ComboBox doesn't suggests words after Space is clicked

I have a ComboBox in which i have a list of words;

for e.g.

Apple

Mango

Banana

when i type A it suggests me words starting with A i.e. Apple. Now when i click on apple and click on Space i.e. "Apple " and types next alphabet say M i.e. "Apple M" it doesn't suggests Next word.

After space is clicked it stops suggesting. Please provide your feedbacks