Ctrl+pick block creates an exact copy of the block at hand, including NBT data and tile entities. However, I have discovered that the block will lose its NBT data if placed inside another container.
How To:
Ctrl+pick block a chest with items inside of it. Take this chest (Chest 1) and store it inside another chest or an ender chest (Chest 2). Close chest 2. Reopen chest 2 and take chest 1 out of it. Place chest 1 down and open it. It will be empty. All the items will be lost.
Is this still a concern in the current Minecraft version? If so, please update the affected versions in order to best aid Mojang ensuring bugs are still valid in the latest releases/pre-releases. If this has been done, we can reopen the issue.
Keep in mind that the "Resolved"-Status on this ticket just means "Answered", and that we are waiting for further information on whether this issue still exists or not. We will reopen it as soon as the requested information has been delivered.