^{Update for 1.2.0.22 by Mega_Spud:}
Although there have been some changes to the way dropped items behave in the 1.2 beta, they can still get stuck inside transparent blocks. Video showing the issue: https://youtu.be/prjuNIXbgZ0

^{Edit by Mega_Spud:}
Verification builds:
1.1.0.9 Retail
1.0.8.1 Retail

Summary:
Dropped items can become stuck inside transparent blocks, instead of being pushed out to the next available space. Under certain circumstances these cannot be picked up by the player until the transparent blocks are broken (eg. Stairs).

(See screenshots)
Steps to Reproduce Example 1: (See example video: https://youtu.be/sfjmxf_pp6s)

1. Create a 3x2x3 cube of glass blocks, with a hollow tube in the middle
2. Drop items into the tube in the middle
3. Fill the tube with glass

Observed Results:
The items move up and then back down into the glass block at the bottom.

Expected Results:
The dropped items should move up to the top of the glass.

Steps to Reproduce - Example 2: (See example video: https://youtu.be/m9-k5ggk2rg)

1. Make a 2x2 hole in the ground
2. Drop items into the hole
3. Place slabs or stairs in the hole

Observed Results:
The items simply stay stuck inside the slabs or stairs

Expected Results:
The dropped items should move up or out to the next available gap.

Screenshots/Videos attached: Yes

Notes:
Original Description:
When I put transparent blocks on dropped items, the items disappeared.