Thick border for a plot

I have a plot like this

As can be seen, there is no border on the right side.

My questions:

1- Why?

2- How to get it solved?

3- How to make the axes thicker (how to change the linewidth of the axes)?

4- How to make a thick border around the plot (the line indicated in red shape)?

Thanks for your help!

Answer 1

[VBBV]

box on
ax = gca
ax.LineWidth = 6

[CS]

Worked. Thanks!

[CS]

However, if we are using the

grid on

all the grid lines would also get thicker. How can I only change the width of the border?

How can I have the grid lines as what they are and change the width of the border?

Answer 2

[CS]

Also, how can I increase the marker size in the legend?

I found somthing realated to icons, but when I apply it, the legend title disappears. How can I have both legend title and enlarged legend marker size?

Thanks!