It Worked. I solved this Heap usage limit error. I made the changes as per what you said on top. But still the Attachments related drawer is not working as expected. the condition and before load action that i am using now looks like this 
I also Added a context condition when the drawer opens. that condition looks like this 
Whenever i have a context enabled, the table is completely empty (no records within the attachments is showed up). When i don’t have the context condition, all the attachments records are showed in the table. Where am i going wrong?
