Splitter: Hard to see when on for left or right side

[adamzhang1932]

Is your feature request related to a problem or use case? Please describe.

Download the zip file,

1.Use the 'example-splitter-demo.html' file.
2.See the video to reproduce the issue.

Difficult to find the splitter bar icon after using the collapse button to shrink the splitter bar to the far left.zip

Step1:
Click the icon, then the splitter bar will reach the far left side.

Step2:
When I move the mouse to the far left, but cannot see the splitter bar.

The only solution is:
I can only see the splitter bar and drag it when I move the mouse to the top left corner. So I think this might be user unfriendly.

Describe the solution you'd like
There is one example which works well after using the collapse button to shrink the splitter bar to the far right.
Download the zip file,
1.Use the 'example-splitter-demo-right.html' file.
2.See the video.
Collapse button works well at the right side.zip

Additional context
Infor SunSystems.

[tmcconechy]

@adamzhang1932 we had talked about this on issues like infor-design/enterprise-wc#1532

What we decided is that the app team should add an expand/collapse button on the top toolbar above the splitter so that they can toggle the splitter and open it when its completely collapsed.

So to solve this consider the addition of a button. We may provide an example for this in the future.

[tmcconechy]

TODO: Make an example with a splitter and a button on the toolbar. The button will toggle collapse state