MATLAB: Can not make Legend border visible

figurelegendMATLAB

With the code below. This the example code from https://www.mathworks.com/help/matlab/ref/legend.html
x = linspace(0,pi);
y1 = cos(x);
plot(x,y1)
hold on 
y2 = cos(2*x);
plot(x,y2)
legend('cos(x)','cos(2x)')
I got
The legend looks like this, which I can not understand.
If you check the last question I raised. All my figures have some problems with the legend. I do not know why. It seems that I need to change some settings of the matlab. The 2019b and 2020a both have this legend problem.
It looks like a very basic question. But it really annoys me for some time.
Any help, many thanks!

Best Answer

This is a problem with certain AMD graphics drivers.
First, see if there is an update for the AMD driver. If so, let the AMD software update it for you.
In the interim, use: 
opengl('software')
and if you want to save that for future sessions: 
opengl('save','software')
However, it would be best to update the driver before you use the 'save' option. In the latest AMD driver versions, this is no longer a problem.
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