window minimization

  the window containing a monster card minimizes as soon as I click on the summary bar, (or anywhere else like on the map for example), preventing me from dragging a spell into the card to add it to my library.  does the same happen to anyone?  can you help me?  thanks to everyone for your attention

I am guessing you are popping the window out of the game. Don't pop it out of the game when trying to make alterations to it such as adding spells.  If that is not what is happening please supply a screenshot showing the problem.

Hi and thank you very much for your reply, in the first image I have the monster window open in the spells section, in the next image if I "click" on any spell to drag it, the window is reduced to an icon, preventing me from inserting the spell  

As previously stated, you are popping the window out, don't do that if you plan on making changes to the sheet that are more than changes to numbers. 

forgive me, for my familiarity with this program, but how do I prevent roll20 from opening a new window? or rather how do I keep the window in the game? because I think you have identified the problem but I don't know how to fix it. thanks again very much for the replies

When you open the character you have to push a button to pop it out. It is a step you are performing.  I have highlighted the button you are pushing in red below. Don't push that button and it won't pop out. 

Alternatively, you may have the option turned on in the in-game settings to automatically pop out character sheets into their own window.  Make sure that box is NOT checked in the top section of settings (Personalization and Display).

Good point, I forgot about that setting.  @idaos i., Here is a screenshot of that setting, make sure it is unchecked. 

If you want to use compendium items for your character sheet, as all others said, it has to be displayed inline as it does not work for pop out character sheets... idaos i. said:  the window containing a monster card minimizes as soon as I click on the summary bar, (or anywhere else like on the map for example), preventing me from dragging a spell into the card to add it to my library.  does the same happen to anyone?  can you help me?  thanks to everyone for your attention

Great, excellent, problem solved. It was enough to uncheck the option as indicated, thank you, thank you very much.