Wire Version: don't know, because I can't show the main menu... It was downloaded from your web and installed today (25.8.2017, the deb package).
OS: Kubuntu LTS 16.04
Do you have an antivirus software installed: no
What steps will reproduce the problem?
What is the expected result?
Being able to unhide main menu. I have tried alt hotkey which should work on Windows, but it did nothing.
What happens instead?
Main menu remains hidden. Restart of the application doesn't help.
Please provide any additional information below. Attach a screenshot if
possible.
I don't think it's necessary posting a screenshot with hidden main menu...
Unfortunately the ALT key is not reliably showing the menu again once you hid it. We are aware of the issue. Usually you can click the title bar of the application and click the ALT key at the same time to unhide it. Then simply select the menu option again to keep it sticky once more.
On Windows 10 I can always use ALT to show the menu again if I am in the Options/Preferences page. In the normal view it doesn't work, in options it does.
^ Observing the same as FHTHeron on dwm (Linux). Is it an option to include the show/hide setting in the preferences page?
This happened to me today on Windows 10. No amount of clicking Alt + mouse, Alt by itself, or any other keys apparently, will give me the option to "undo" hide main menu.

how can I fix this ?
Alt key is not working
@chemistmertkoc This does not seem to be related to Wire.
@mnn Did you try clicking on the account selector space and then pressing Alt?
I found this key combination to be a reliable workaround to show the hidden menu:
AltAltDoing steps 1-3 once time will show the menu, repeating 1-3 will hide menu again.
Most helpful comment
On Windows 10 I can always use ALT to show the menu again if I am in the Options/Preferences page. In the normal view it doesn't work, in options it does.