private int checkKeyCombination(KbDllHookStruct kbDllHookStruct)
{
int code = -1;
// check key combination
if (kbDllHookStruct.vkCode == extendParagraphKey && checkHotkeysModifiers("extendParagraph"))
code = ExtensionMode.EXTENDPARAGRAPH;
else if (kbDllHookStruct.vkCode == reduceParagraphKey && checkHotkeysModifiers("removeParagraph"))
code = ExtensionMode.REMOVEPARAGRAPH;
else if (kbDllHookStruct.vkCode == extendSentenceKey && checkHotkeysModifiers("extendSentence"))
code = ExtensionMode.EXTENDSENTENCE;
else if (kbDllHookStruct.vkCode == reduceSentenceKey && checkHotkeysModifiers("removeSentence"))
code = ExtensionMode.REMOVESENTENCE;
else if (kbDllHookStruct.vkCode == extendWordKey && checkHotkeysModifiers("extendWord"))
code = ExtensionMode.EXTENDWORD;
else if (kbDllHookStruct.vkCode == reduceWordKey && checkHotkeysModifiers("removeWord"))
code = ExtensionMode.REMOVEWORD;
return code;
}