inkscape version: 1.3.2

inside SHIFT+CTRL+L -> layers and objects

if you select multiple paths of a layer, by pressing CTRL or SHIFT and click on paths, the whole selection will be gone, if you then call the contextmenu (click on right mouse button), to decide what do with the selection.

In any other program the selection got not killed by calling a context menu, thats the sense first select and then call context, what do with it.

How can i keep selection alive?

This is a known issue https://gitlab.com/inkscape/inkscape/-/issues/4721

Hopefully resolved by next release.

Please note that if a right clic doesn't work in object panel, you can right clic on canvas on any already selected object (eventually use numpad  key 3 to zoom on selected objects), without exiting the selection you did by using object panel.