Alt button not detected on some keymap shortcut IntelliJ (elementaryOS 5.1.7

Settings

• IntelliJ 2019.2 (same issue in 2020.2)
• elementary OS 5.1.7.
• AZERTY bluetooth Keyboard (Logitech K260)
• French Keyboard Layout
• French Input method
• No custom configuration made either in IntelliJ or in the OS

Problem

The "Move Line Up/Down" shortcut I was using on Windows (Shift + Alt + Up/Down) is not working.

Description

On intelliJ, I opened Settings/Keymap window to check the shortcut was correctly set. When trying to redefine this shortcut, the "Alt" button was not detected when pressed.

However, I can use it on elementaryOS (e.g. Alt+Tab is working).

On intellij, I can use some other shortcuts like "Alt + Up".

My OS were recently installed.

I already tried to put UK layout/input method with no success.

Two ideas:

• system settings : something i missed in keyboard settings ? Don't know much about linux configurations.
• IntelliJ option i'm missing.

Thanks.

Finally found the issue.

On elementaryOS,

• Go to your Keyboard settings, select "Layout" tab.
• On "Switch layout" options, change the default shortcut "Alt + Shift".

Then I am able to reuse this specific shortcut in IntelliJ.

See the screenshot below to get more information: Keyboard/Layout/Switch layout