avoid context menu over treeview, when form is disabed
avoid context menu over treeview, when form is disabed

Alexey-T/CudaText,Alexey-T/CudaText,Alexey-T/CudaText,Alexey-T/CudaText,Alexey-T/CudaText,Alexey-T/CudaText,Alexey-T/CudaText,Alexey-T/CudaText