Line Segment Tool: First line disappears when drawing the second line

[Aron32765378zjbm]

Why does my first line disappear when I draw a new line? 

I'm trying to draw a grid, but my lines are disppearing when I start the next line. In the first image, you can see the new line (in blue). In the second image you can see what happens after I click to start the next line (the first line disappears). Why is this happening ? 

The lines worked until I added an image to the document. When the image is there, the issue started. I deleted the image and the issue persists.

[Aron32765378zjbm]

I want to add that the layers are appearing (3 bottom layers in the image). But, if you look closely you'll see there are no lines on the layers - they look like blank pages. Unlike the layers above, where you can see the lines.

If I select one of the bottom three layers the line will appear on the document. But I can only see one of those lines at a time and the layer has to be selected for it to appear. I can't have all of them appear at the same time with the rest of the lines. 

[Ton Frederiks]

What color does the line have?

[Aron32765378zjbm]

Looks like I needed to edit the size and colour of the line in the Properties settings. Its weird that they change every time I create a new line. Thanks!

[Monika Gause]

So when you select a line, apply a stroke and then directly draw a new line, then it is again without a stroke?