Menu bar items/entries do not respond to user's keyboard input.
On Windows it works as expected.
On Mac it selects a random entry.
On Linux it does not select anything.

Steps:
1. Create a New Project
2. Open any menu bar item, for example, Assets
3. Try to select "Refresh" item by clicking 'R' button on a keyboard twice

Expected behavior: "Refresh" is selected.
Actual behavior: random item is selected.

Reproduced with: 2017.3.0b1, 5.5.5f1, 5.3.8f1.

Updated Info:

The MacOS Menu Bar doesn't function as described in the repro steps: "Try to select "Refresh" item by clicking 'R' button on a keyboard twice".

According to the official Apple documentation (https://support.apple.com/en-us/HT204434):
Jump to a menu item in the selected menu - Type the menu item's name

Although cycling through menu items by just pressing the first letter of the item's name does sometimes work, it's not the officially supported way. You can see this behavior in other apps, e.g. Chrome: open the "File" menu and press 'N' to try and cycle between "New Tab", "New Window", etc. and you'll find it doesn't work.