Before explaining SymbolsPanel, I would like to introduce the japanese input method "Simeji" made by adamrocker.
Simeji is the "japanese" input method, but it has also "qwerty" keyboard. When viewed as a qwerty keyboard, you may feel Simeji is not attractive.
"Mushroom" is the important feature characterizing Simeji. By installing Mushroom plugins, Simeji's features will be expanded. Calling plugins is very easy --- just press Mushroom button.
If some plugins are installed on your device, a list of plugins is displayed. select one you wish.
By implementing as an input method plug-in, applications will be able to send text directly into the input area. Also on SymbolsPanel, there is no need to send via the clipboard. In other words, you will no longer need "Paste" operation.
If you are dissatisfied that SymbolsPanel is not a input method, please try to use with Simeji. Your dissatisfaction would be resolved, I think.
Incidentally, the origin of the name "Simeji" is:
>The name "simeji" is an abbreviation of "Social IME ji." Ji means "characters" in Japanese.
...Freeware Offers Japanese Language for Android - Tech-On!
>Shimeji is a group of edible mushrooms native to East Asia, but also found in northern Europe.
...Shimeji - Wikipedia