You probably didn't know all of them...
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Ctrl+Shift+1:
contextual code generation (it's MAGIC!)
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Ctrl+Space: contextual completion list - also, press
Tab to expand snippets like 'for', 'while', etc.
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Ctrl+Shift+Space: method call-tip (the yellow window with current method's signature)
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Ctrl+Alt+Space: list all project classes (as after ':' or keywords like "new")
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F4: go to declaration of element at cursor location.
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Shift+F4: jump back after F4 or code generation.
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F1: when you see "..." in a (yellow) tip, you can press F1 to see a more detailed tip.
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Escape: Close the completion list and method call-tip (or press
Ctrl key to hide them).