I can't run my windows form?

I wanted to run one of my windows form using the Application.Run(new FormName);
But I can't, because my formname is underlined with red, even I typed the correct formname. Can someone help me?
I'll give a link to the pic.
https://imgur.com/Oslml45
The formname is correct there.

2019-05-12T12:22:58Z

I tried to run it. It opened the other form instead, not the one I'm trying to open right now.
It opened the last correct formname I entered.

Chris2019-05-12T22:28:31Z

C# doesn't know what Compile1 is referring to. You need to import the class first, by putting something like

using Compile1;

at the start of your program.

Jeff2019-05-12T12:06:25Z

Underlined red means the word is seen as misspelled but it won’t affect your code so you should be fine.