I have a few svg's that I want to alter.
I want to alter them by manipulating some nodes - including deleting some nodes.

I want to select a some nodes at once, without selecting all nodes at the same time.

So I activate the node tool and select on one object inside the canvas.
When I select one object in the canvas with the node tool, all nodes in all objects in the canvas become active.
So clicking 'delete' would delete all nodes.

I thought that maybe all the objects were grouped.
So with all nodes selected, I click on 'object' -> 'ungroup'.

Then with the node tool selected, I click on one object.
But the same thing happens again: all nodes across all objects get selected.

How can I just select one or a a few nodes without selecting all nodes?

 

This is absolutely doable by default; the Node tool makes the nodes just visible and with click plus shift-click you can add and subtract from a node selection: dark blue nodes are selected ones. So why everything gets selected by just hitting one node escapes me. Perhaps check Inkscape‘s Preferences->Selection/Node tool if something isńt set up as you like wish to.