Beamer Export Columns

[Georgios Marentakis <marentakis@iem.at>]

Hallo, 

I am using the org beamer functionality to produce presentations and I am quite happy with it. Saves a lot of time. Thanks for the great work!

There is one thing however I am not sure how to go about. I have found a number of answers in the mailing list but none that works for me. 

The question is about (top) aligning columns in beamer export mode. 

The following indeed produces two top aligned columns C1 and C2. 

* Frame
	:PROPERTIES:
	:BEAMER_env: frame
	:END:
	* Columns
		:PROPERTIES:
		:BEAMER_env: columns
		:BEAMER_opt: t
		:END:
		* C1
		:PROPERTIES:
		:BEAMER_col: 0.45
		:BEAMER_env: block
		:END:
		* C2
		:PROPERTIES:
		:BEAMER_col: 0.45
		:BEAMER_env: block
		:END:

My questions:

1. Given that the columns environment is implied by the BEAMER_col property, is there anyway to avoid the Columns heading by passing the t option implicitly to the columns environment?
	Deleting the Columns entry and setting :BEAMER_envargs: C[t] or c[t] or C[T] or c[T] in the Frame or the C1/C2 headings is not producing top aligned columns for me.

2. What is the status of BEAMER_opt and BEAMER_envargs properties?
	Are they both still supported and what exactly is the difference?

Some more general questions: 

3. Why is the heading of a BEAMER_col entry ignored by default? Why does one have to specify a block environment in order for the heading to be visible? 

4. In some cases the BEAMER_col property results in subsections instead of columns in the tex file, why is this?  


many thanks, 
georgios