Lagging in math command completion combo box

[Zohar Levi]

When I'm inside a math environment (ctrl+m), and I start to write a symbol 
"\math", Iyx immediately shows in a faded text a correct completion "\mathbb". 
Then, I need to wait a few seconds until a combo box with all the options would 
pop up, and only then I can press enter and select "\mathbb". Is there a way to 
immediately accept a suggestion without waiting for the combo box? For example, 
in visual studio it's done with ctrl+space.