Issue type

I'm submitting a ...

• bug report
• feature request

Issue description

• NbContextMenu stops working after parent element/component is "refreshed".

Current behavior:

• After "refreshing" the element/component, every NbContextMenu inside that element/component stops working.
• PS: By refreshing I don't mean using "F5", but by detaching and then attaching the parent element (or component) by custom directive (you can see that in repro).

Expected behavior:

• After "reattaching" the element/component, every NbContextMenu located in that element/component should still be working.

StackBlitz repro:

• https://stackblitz.com/edit/github-fnq8mz

Steps to reproduce:

• Open atleast once the NbContextMenu (by clicking on ContextMenu button) and then click "call directive refresh method" button. After that, every NbContextMenu inside the div element in app.component stops working and you aren't able to open it again.

Other information:

OS: propably ALL (tested on Windows 10)
Browser: propably ALL (tested on Chrome, Firefox)
Angular: 7.1
Nebular 3.1
Node: 8.9.4

All versions you can see of course in the StackBlitz repro