The width of the list is set by the width of the folder pane divider on the left of the screen and the message divider on the right. In the end the total width of the displayed panes is 100% of the window. So if you want to make the far right column smaller you need to reduce the space allocated to the list over all be either making the folder pane wider or the message displayed on the right wider, or if you have the today pane, you could also make that wider. The list gets what is leftover after the other panes are set for width.

if i point to date i get the blue icon and i can resize... if i point to location again i can resize. the last column on the right NO MATTER WHAT IT IS, cant be resized. so here, for example, i cant make the tags smaller

if i point to date i get the blue icon and i can resize... if i point to location again i can resize. the last column on the right NO MATTER WHAT IT IS, cant be resized. so here, for example, i cant make the tags smaller

I thought that was what I told you. Tags as he last column can only be made smaller only by making the column to the left of it larger, or adding another column after it which will then have the same issue you can only reduce it's size by making the column to it's left larger.