How can I make the lines of a table visible?

[Hapax]

I have created a table, whose lines I want to make visible. When I type in F2, then I see a button called "lines", and the line-colour is set to "black". Since I do not see any lines, I thought that my lines were simply too thin. Even after setting the line-width to 20pt, I could not see any lines separating the segments of the table. What should I do? 

[Arran]

You then select the button «colour» and set the line colour. Pay attention not to pick the fill tool.

[Jupeku]

I dont get it work when i want change whole table colour sometimes selecting works sometiomes not. Totally random way work but one tip form me if some one needs group and ungroup it then you can change whole table colours hard tell more.
ps. i still dont know how i can search and replace values in table looks like its impossible. I know this is not spreadsheet but spreadsheet done table importing dont work well.