Potential fix: Running the Keymapper (Ctrl+F1) and exiting it seems to reset the tab-key. Although its a temporary solution. You can also remap the tab-key to another key (though tiresome to use), then it will always work with the new key. Though this is not recommended. Another bug I have here is that the Keymapper is black after starting. Hiting on random places with the mousebutton will fix this.
Potential fix: Running the Keymapper (Ctrl+F1) and exiting it seems to reset the tab-key. Although its a temporary solution. You can also remap the tab-key to another key (though tiresome to use), then it will always work with the new key. Though this is not recommended. Another bug I have here is that the Keymapper is after starting. Hiting on random places with the mousebutton will fix this.
tab key not working after alt+tab in Windows 10