I like this feature and I wanted this feature to be implemented as I had similar problems that the OP stated. However, I see some problems that might occur if implemented. The list of items available in market is refreshed every time the item is clicked on the search results list. So if somebody listed something (or somebody bought something), it will not show up unless the list is refreshed. The time it may take to select the items you want to buy might be too long and another player might've already bought one the item you selected. Therefore, an error would occur and you wont be able to buy the unlisted item. Frequent refresh of the list might also not be a good idea as it might overload the servers.