I had felt that "I want to delete a character press the wrong symbol, but that operations is troublesome." Then, since v0.9d, the deleting feature by flicking "Apply/Copy" key to left was added. But it is not intuitive. Placing a delete button would be better? But, considering a mistake, there is no place to put it...
As a compromise, "Delete by BACK key" feature was implemented. This feature also prevents to quit app by accidentally press BACK key.
Another new feature is "Shrink-On-Edge." This is able to display the original input area hidden by SymbolsPanel, and check the entered text.
But, this may not be practical because the shrunken panel may be too small depending on the screen resolution (in particular, if the software keyboard is displayed.) In that case, after checking the text, you can restore the panel size (by tap the outside of the frame), then enter symbols.
In this version, the greek letters are added into the default settings of buttons.
In a policy of SymbolsPanel, the usual letters of each country would not implemented. But, the greek letters are used as mathematical/technical symbols. Also it was requested. So I decided to adopt it.
For users who wanted to apply the default settings manually, the default settings of SymbolsPanel 0.9f is at same place as before (See this article for how to apply manually.)