After re-installing inkscape I have noticed some settings are changed but I do not know what or how?
This is what I am trying to do.

A straight rectangle. At the top added one extra node which make them total three nodes. Deleted two and kept the middle node. After that it is supposed to be straight pointed one but it isn't. Last image is not proper.
Here is a screen shot showing sequence how I did that.


I know if I use ctrl+left mouse and drag the center node up I can achieve that what I want. But I think it should also be done by deleting nodes as I mentioned above.

Please advice what I am suppose to do.

Thank you

Hold Ctrl when you delete the nodes

Or if you'd like this to be the default behavior, you could go to Inkscape Preferences > Tools > Node > 'Deleting nodes preserves shape' and uncheck that option.

Brynn's reply is the best solution, but if you want to straighten a curved path segment after the fact:

1) Switch to the node tool
2) Select the end nodes of the segment(s) you want to straighten. For a single segment the fastest way is to click on the segment itself, but in this case you could safely select all the nodes in the path (CTRL-A).
3) On the tool control bar, click the "Make selected segments lines" button (11th icon).

Thank you Brynn and Xav.

I followed the method explained by both of you and decided it will be easier for me:
Inkscape Preferences > Tools > Node > 'Deleting nodes preserves shape' and uncheck that option.

I appreciate your help.

Thank you