Tile/Wall selection severely borks itself after about 5-10 minutes of TEdit usage

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Windows 10
Tedit Version 4.12.0
Terraria 1.4.4.9

After a short period of time using TEdit, alternating usage of the Picker and Pencil tools, selection breaks for both the Tile and Wall drawers. I can't seem to reproduce it with a specific pattern of actions, it just happens after the aforementioned time frame, with no exceptions,
When clicking on the down arrow for selecting a Tile/Wall, it will only display the last used one. Deleting the search text doesn't work, and the search function itself breaks. Here's a before and after (note that the latter picture shows what happens upon inputting any text):

Using the Picker tool on anything seems to fix this, but the search function will remain broken until the next restart. Basically, when typing something and pressing enter, the program will simply pick Air, probably because it's the first on the list, and be stuck with Air until you use the picker tool again. Here's a before and after for this aswell (again, entering any search term yields Air as a result):

Lastly, in what seems to be completely random intervals after this problem occurs, the Tile/Wall aswell as Mask windows will show blank, despite a specific Block/Wall/Mask being selected. Here's proof of before and after use of the Pencil tool: