I do not have a solution but the same problem. It seems to be attached to my user ID some how because it follows me to to different PCs as well as the core server. If some one else logs in to the console it comes up normally. This just began about a week or two ago for me.
I found a fix for it! Thankfully!
In your console click on Configure > Layouts > then click on the rest button. This should allow the window to come up for you again.
This happens to me once in a while, an easy fix once you learn how...
Actually, there are two similar issues, here is the description and fix for both and a tip to help you out in the future...
Issue # 1
Right click on the item in the taskbar, choose "Maximize"
If this opens it, close the window, reopen it, now you can resize it and close it again, this will "remember" your setting / size
Issue # 2
If the above does not open it, it is most likely "off the screen", this happens when you open the console on a dual-monitor system and have the windows open on two different screens, or in some cases, all open on the "secondary" monitor. Now, when you open the console on a Single screen system or RDP'd tot he core, some windows will be opened on the other screen.... the one you don't have!
To fox this, right click on the item in the task bar
Select the "move" option from the right click context on the task bar tab.
Then use the Keyboard arrows, not the mouse, to move the window into position.
It should return to the position you move it to on future starts.
What I found works great is to get all of your LANDesk console items set up the way you want on your RDP / Teminal session (or any single screen setup), go to "Layouts" at the top, save it as "Terminal" or some other name.
Now, open on your desktop and repeat, saving with a new name.
Now, if you ever get into this issue, you can just go to your layouts and apply the one you want.