ContentPlaceholder not appearing on own template applying th

Hello,

I am trying to create our own template for sitefinity (.master) and our own theme (.css) and i have some troubles with some contentplaceholder.
I have put these files in App_Theme and App_Master directories in Websitetemplates in App_Data.
I have created a new theme with my css file and a new template with my master file in sitefinity backend.
When I create my template, my all 3 content placeholder are visible but when i apply my theme 1 disappears. I try to preview it and inspect the HTML code. In fact the div where the contentplaceholder should be is 0px witdh and height.
Is it why the contentplaceholder is not appearing?
If it is yes, I don't understand why i can see the others as my others div are also 0px height.

Do you have any advice to build our .master and .css file when the desired template is not based on a simple table construction (even with div) ?

Thank you for your help.

Sorry this was a response for another post, my apologies.

Sorry, but...

What is the addmarker function?
What about map?
Why is undefined?

Hello Stephane,

 As a whole ContentPlaceHolders are not visible when placed in a 0px height div. I cannot conclucde why only one of them disappears (maybe you assigned the particular class only to its ID). Additionally you will do good to share the code of your template and css as this will provide us with more resources for us to work with and in turn a better explanation. 

You can also review the information concerning page themes in our Documentation.